diff --git a/process/core/io/vary_run/config.py b/process/core/io/vary_run/config.py
index c267881d6a..a289cc13b3 100644
--- a/process/core/io/vary_run/config.py
+++ b/process/core/io/vary_run/config.py
@@ -280,7 +280,8 @@ def setup(self):
         )
         data_structure.global_variables.fileprefix = str(self.wdir / self.infile)
 
-    def run_process(self, input_path: Path, solver: str = "vmcon"):
+    @staticmethod
+    def run_process(input_path: Path, solver: str = "vmcon"):
         """Perform a single run of PROCESS, catching any errors.
 
         Parameters
diff --git a/process/core/scan.py b/process/core/scan.py
index 7a33222c49..30c157676b 100644
--- a/process/core/scan.py
+++ b/process/core/scan.py
@@ -664,7 +664,8 @@ def post_optimise(self, ifail: int):
                 ),
             )
 
-    def verror(self, ifail: int):
+    @staticmethod
+    def verror(ifail: int):
         """Routine to print out relevant messages in the case of an
         unfeasible result from a VMCON (optimisation) run
 
@@ -952,7 +953,8 @@ def scan_2d(self):
         )
         print(f"\nConvergence Percentage: {converged_percentage:.2f}%")
 
-    def scan_2d_init(self):
+    @staticmethod
+    def scan_2d_init():
         process_output.ovarin(
             constants.MFILE,
             "Number of first variable scan points",
@@ -1051,7 +1053,8 @@ def scan_2d_write_point_header(self, iscan, iscan_1, iscan_2):
 
         return iscan_r
 
-    def scan_1d_write_plot(self):
+    @staticmethod
+    def scan_1d_write_plot():
         if scan_variables.first_call_1d:
             process_output.ovarin(
                 constants.MFILE,
diff --git a/process/main.py b/process/main.py
index d6835f92c9..ab68dabac9 100644
--- a/process/main.py
+++ b/process/main.py
@@ -96,7 +96,10 @@
     PlasmaBeta,
     PlasmaInductance,
 )
-from process.models.physics.plasma_current import PlasmaCurrent, PlasmaDiamagneticCurrent
+from process.models.physics.plasma_current import (
+    PlasmaCurrent,
+    PlasmaDiamagneticCurrent,
+)
 from process.models.physics.plasma_fields import PlasmaFields
 from process.models.physics.plasma_geometry import PlasmaGeom
 from process.models.physics.plasma_profiles import PlasmaProfile
@@ -444,11 +447,13 @@ def run_scan(self):
             )
         self.scan = Scan(self.models, self.solver, self.data)
 
-    def show_errors(self):
+    @staticmethod
+    def show_errors():
         """Report all informational/error messages encountered."""
         show_errors(constants.NOUT)
 
-    def finish(self):
+    @staticmethod
+    def finish():
         """Run the finish subroutine to close files open in the Fortran.
 
         Files being handled by Fortran must be closed before attempting to
diff --git a/process/models/availability.py b/process/models/availability.py
index 9040871468..aca0568a3f 100644
--- a/process/models/availability.py
+++ b/process/models/availability.py
@@ -783,11 +783,9 @@ def calc_u_unplanned_divertor(self, output: bool) -> float:
         # Integrating the instantaneous availability gives the mean
         # availability over the planned cycle life N
         if self.data.costs.div_nu <= self.data.costs.div_nref:
-            logger.error(
-                """div_nu <= div_nref
+            logger.error("""div_nu <= div_nref
             The cycle when the divertor fails with 100% probability <= & Reference value for cycle life of divertor
-            """
-            )
+            """)
             po.ocmmnt(
                 self.outfile,
                 "ERROR: The cycle when the divertor fails with 100% probability & <= Reference value for cycle cycle life of divertor",
@@ -895,11 +893,9 @@ def calc_u_unplanned_fwbs(self, output: bool) -> float:
         )
 
         if self.data.costs.fwbs_nu <= self.data.costs.fwbs_nref:
-            logger.error(
-                """fwbs_nu <= fwbs_nref
+            logger.error("""fwbs_nu <= fwbs_nref
             The cycle when the blanket fails with 100% probability <= &Reference value for cycle life of blanket
-            """
-            )
+            """)
             po.ocmmnt(
                 self.outfile,
                 "EROROR: The cycle when the blanket fails with 100% probability& <= Reference value for cycle life of blanket",
@@ -1029,7 +1025,8 @@ def calc_u_unplanned_bop(self, output: bool) -> float:
 
         return u_unplanned_bop
 
-    def calc_u_unplanned_hcd(self) -> float:
+    @staticmethod
+    def calc_u_unplanned_hcd() -> float:
         """Calculates the unplanned unavailability of the heating and current drive system
 
 
diff --git a/process/models/blankets/blanket_library.py b/process/models/blankets/blanket_library.py
index 8975142f9e..f0ec7d9680 100644
--- a/process/models/blankets/blanket_library.py
+++ b/process/models/blankets/blanket_library.py
@@ -3239,8 +3239,8 @@ def pipe_hydraulic_diameter(self, i_channel_shape):
             f"i_channel_shape ={i_channel_shape} is an invalid option."
         )
 
+    @staticmethod
     def elbow_coeff(
-        self,
         radius_pipe_elbow: float,
         deg_pipe_elbow: float,
         darcy_friction: float,
@@ -3490,8 +3490,9 @@ def calculate_basic_geometry(self):
             b_bz_liq=self.data.fwbs.b_bz_liq,
         )
 
+    @staticmethod
     def blkt_outboard_poloidal_plasma_angle(
-        self, n_divertors: int, deg_div_poloidal_plasma: float
+        n_divertors: int, deg_div_poloidal_plasma: float
     ) -> float:
         """Calculate the poloidal angle subtended by the outboard blanket at the
         plasma mid-plane.
@@ -3571,8 +3572,8 @@ def calculate_blkt_outboard_poloidal_plasma_angle(
             )
         )
 
+    @staticmethod
     def calculate_blanket_outboard_module_geometry(
-        self,
         n_blkt_outboard_modules_toroidal: int,
         rmajor: float,
         rminor: float,
@@ -3647,8 +3648,8 @@ def calculate_blkt_inboard_poloidal_plasma_angle(
             2.0 * np.arctan(dz_blkt_half / (rminor + dr_fw_plasma_gap_inboard))
         )
 
+    @staticmethod
     def calculate_blanket_inboard_module_geometry(
-        self,
         n_blkt_inboard_modules_toroidal: int,
         rmajor: float,
         rminor: float,
diff --git a/process/models/blankets/hcpb.py b/process/models/blankets/hcpb.py
index 774cb18a4d..b62ecc5d6f 100644
--- a/process/models/blankets/hcpb.py
+++ b/process/models/blankets/hcpb.py
@@ -598,8 +598,8 @@ def nuclear_heating_magnets(self, output: bool):
                 self.data.tfcoil.m_tf_coils_total,
             )
 
+    @staticmethod
     def nuclear_heating_fw(
-        self,
         m_fw_total: float,
         fw_armour_u_nuc_heating: float,
         p_fusion_total_mw: float,
@@ -640,8 +640,9 @@ def nuclear_heating_fw(
             )
         return p_fw_nuclear_heat_total_mw
 
+    @staticmethod
     def nuclear_heating_blanket(
-        self, m_blkt_total: float, p_fusion_total_mw: float
+        m_blkt_total: float, p_fusion_total_mw: float
     ) -> tuple[float, float]:
         """Calculates the nuclear heating in the blanket for the CCFE HCPB model.
 
@@ -685,8 +686,8 @@ def nuclear_heating_blanket(
 
         return p_blkt_nuclear_heat_total_mw, exp_blanket
 
+    @staticmethod
     def nuclear_heating_shield(
-        self,
         itart: int,
         dr_shld_outboard: float,
         dr_shld_inboard: float,
@@ -988,7 +989,8 @@ def powerflow_calc(self, output: bool):
                     self.data.fwbs.radius_blkt_channel_180_bend,
                 )
 
-    def st_cp_angle_fraction(self, z_cp_top, r_cp_mid, r_cp_top, rmajor):
+    @staticmethod
+    def st_cp_angle_fraction(z_cp_top, r_cp_mid, r_cp_top, rmajor):
         """
         Estimates the CP angular solid angle coverage fration
         Equation (1-3) from
diff --git a/process/models/build.py b/process/models/build.py
index 0c7daea60f..f9bf46a6c9 100644
--- a/process/models/build.py
+++ b/process/models/build.py
@@ -55,8 +55,8 @@ def run(self):
             dx_beam_shield=self.data.current_drive.dx_beam_shield,
         )
 
+    @staticmethod
     def calculate_beam_port_size(
-        self,
         f_radius_beam_tangency_rmajor: float,
         rmajor: float,
         n_tf_coils: int,
@@ -1458,8 +1458,8 @@ def divgeom(self, output: bool):
                 )
         return divht
 
+    @staticmethod
     def plasma_outboard_edge_toroidal_ripple(
-        self,
         ripple_b_tf_plasma_edge_max: float,
         r_tf_outboard_mid: float,
         n_tf_coils: int,
diff --git a/process/models/costs/costs_2015.py b/process/models/costs/costs_2015.py
index 69158a8143..579270d23d 100644
--- a/process/models/costs/costs_2015.py
+++ b/process/models/costs/costs_2015.py
@@ -1236,7 +1236,8 @@ def calc_remaining_subsystems(self):
         for j in range(35, 60):
             self.data.costs_2015.s_cost[60] += self.data.costs_2015.s_cost[j]
 
-    def value_function(self, x):
+    @staticmethod
+    def value_function(x):
         """Value function
         Function for separative work unit calculation for enrichment cost
         PROCESS Costs Paper (M. Kovari, J. Morris)
@@ -1244,7 +1245,8 @@ def value_function(self, x):
         """
         return (1.0e0 - 2.0e0 * x) * np.log((1.0e0 - x) / x)
 
-    def ocost(self, file, descr, vname, value):
+    @staticmethod
+    def ocost(file, descr, vname, value):
         """Routine to print out the code, description and value
         of a cost item from array s in costs_2015
 
diff --git a/process/models/divertor.py b/process/models/divertor.py
index 77690a8e0f..4b20d8726c 100644
--- a/process/models/divertor.py
+++ b/process/models/divertor.py
@@ -372,8 +372,8 @@ def divwade(
             )
         return self.data.divertor.pflux_div_heat_load_mw
 
+    @staticmethod
     def incident_radiation_power(
-        self,
         p_plasma_rad_mw: float,
         f_ster_div_single: float,
         n_divertors: int,
@@ -396,8 +396,8 @@ def incident_radiation_power(
         """
         return p_plasma_rad_mw * f_ster_div_single * n_divertors
 
+    @staticmethod
     def incident_neutron_power(
-        self,
         p_plasma_neutron_mw: float,
         f_ster_div_single: float,
         n_divertors: int,
diff --git a/process/models/ife.py b/process/models/ife.py
index a66c7cf3a5..8e46671f5e 100644
--- a/process/models/ife.py
+++ b/process/models/ife.py
@@ -1460,7 +1460,8 @@ def ifephy(self, output: bool = False):
             self.data.physics.pflux_fw_neutron_mw,
         )
 
-    def driver(self, edrive, gainve, etave):
+    @staticmethod
+    def driver(edrive, gainve, etave):
         """Routine to calculate parameters of a generic driver
         suitable for inertial fusion energy
 
@@ -1512,7 +1513,8 @@ def driver(self, edrive, gainve, etave):
 
         return gain, etadrv
 
-    def lasdrv(self, edrive):
+    @staticmethod
+    def lasdrv(edrive):
         """Routine to calculate parameters of a laser driver
         suitable for inertial fusion energy
 
@@ -1569,7 +1571,8 @@ def lasdrv(self, edrive):
 
         return gain, etadrv
 
-    def iondrv(self, edrive):
+    @staticmethod
+    def iondrv(edrive):
         """Routine to calculate parameters of a heavy ion driver
         suitable for inertial fusion energy
 
diff --git a/process/models/pfcoil.py b/process/models/pfcoil.py
index 396976e8cf..220feac0c7 100644
--- a/process/models/pfcoil.py
+++ b/process/models/pfcoil.py
@@ -1531,7 +1531,8 @@ def tf_pf_collision_detector(self):
                                 "One or more collision between TF and PF coils. Check PF placement."
                             )
 
-    def solv(self, n_pf_groups_max, n_pf_coil_groups, nrws, gmat, bvec):
+    @staticmethod
+    def solv(n_pf_groups_max, n_pf_coil_groups, nrws, gmat, bvec):
         """Solve a matrix using singular value decomposition.
 
         This routine solves the matrix equation for calculating the
@@ -2876,7 +2877,8 @@ def outvolt(self):
                     * self.data.pf_coil.n_pf_coil_turns[k],
                 )
 
-    def selfinductance(self, a, b, c, n):
+    @staticmethod
+    def selfinductance(a, b, c, n):
         """Calculates the selfinductance using Bunet's formula.
 
 
@@ -2993,8 +2995,8 @@ def output(self):
     def run(self):
         """This model doesn't need to be run"""
 
+    @staticmethod
     def calculate_cs_geometry(
-        self,
         z_tf_inside_half: float,
         f_z_cs_tf_internal: float,
         dr_cs: float,
@@ -3067,8 +3069,8 @@ def calculate_cs_geometry(
             dr_cs_full,
         )
 
+    @staticmethod
     def calculate_cs_turn_geometry_eu_demo(
-        self,
         a_cs_turn: float,
         f_dr_dz_cs_turn: float,
         radius_cs_turn_corners: float,
@@ -3145,8 +3147,8 @@ def calculate_cs_turn_geometry_eu_demo(
             dz_cs_turn_conduit,
         )
 
+    @staticmethod
     def place_cs_filaments(
-        self,
         n_cs_current_filaments: int,
         r_cs_middle: float,
         z_cs_inside_half: float,
@@ -3606,8 +3608,8 @@ def ohcalc(self):
             )
         self.calculate_cs_self_midplane_axial_stress_time_profile()
 
+    @staticmethod
     def calculate_cs_self_peak_magnetic_field(
-        self,
         j_cs: float,
         r_cs_inner: float,
         r_cs_outer: float,
@@ -3746,8 +3748,8 @@ def output_cs_structure(self):
             "OP ",
         )
 
+    @staticmethod
     def calculate_cs_self_peak_midplane_axial_stress(
-        self,
         r_cs_outer: float,
         r_cs_inner: float,
         dz_cs_half: float,
diff --git a/pyproject.toml b/pyproject.toml
index 1c82d46137..db9ff194e9 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -116,7 +116,7 @@ dependencies = ["pre-commit", "ruff", "ty"]
 
 [tool.hatch.envs.lint.scripts]
 fmt    = ["pre-commit run --all-files --hook-stage manual {args:}"]
-fmt_extra = ["ruff check --select=E501,PLR6301,C901,PLR0904,PLR0911,PLR0912,PLR0913,PLR0914,PLR0915,PLR0916,PLR0917,PLR1702,D100,D101,D102,D103,DOC501,D404,DOC102,D104,D105,PLC1901,S307 {args:.}"]
+fmt_extra = ["ruff check --select=E501,C901,PLR0904,PLR0911,PLR0912,PLR0913,PLR0914,PLR0915,PLR0916,PLR0917,PLR1702,D100,D101,D102,D103,DOC501,D404,DOC102,D104,D105,PLC1901,S307 {args:.}"]
 
 [tool.coverage.report]
 exclude_lines = ["no cov", "if __name__ == .__main__.:", "if TYPE_CHECKING:"]
@@ -165,7 +165,6 @@ max-locals = 17
 "tests/**" = [
     "ARG",
     "PLR2004",
-    "PLR6301",
     "PLR0904",
     "PLC1901",
     "S101",
@@ -237,7 +236,6 @@ ignore =  [
 
     # urgent removal remainder
     "E501",
-    "PLR6301",
     # complexity
     "C901",
     "PLR0904",
diff --git a/tests/integration/test_vmcon.py b/tests/integration/test_vmcon.py
index 1630840081..1b179dc338 100644
--- a/tests/integration/test_vmcon.py
+++ b/tests/integration/test_vmcon.py
@@ -115,7 +115,8 @@ class Evaluator1(CustomFunctionEvaluator):
     :type CustomFunctionEvaluator: CustomFunctionEvaluator
     """
 
-    def fcnvmc1(self, n, m, x, ifail):
+    @staticmethod
+    def fcnvmc1(n, m, x, ifail):
         """Function evaluator.
 
 
@@ -141,7 +142,8 @@ def fcnvmc1(self, n, m, x, ifail):
 
         return objf, conf
 
-    def fcnvmc2(self, n, m, x, lcnorm):
+    @staticmethod
+    def fcnvmc2(n, m, x, lcnorm):
         """Gradient function evaluator.
 
         Calculates the gradients of the objective and constraint functions at
@@ -178,7 +180,8 @@ class Evaluator2(CustomFunctionEvaluator):
     :type CustomFunctionEvaluator: CustomFunctionEvaluator
     """
 
-    def fcnvmc1(self, n, m, x, ifail):
+    @staticmethod
+    def fcnvmc1(n, m, x, ifail):
         """Function evaluator.
 
 
@@ -204,7 +207,8 @@ def fcnvmc1(self, n, m, x, ifail):
 
         return objf, conf
 
-    def fcnvmc2(self, n, m, x, lcnorm):
+    @staticmethod
+    def fcnvmc2(n, m, x, lcnorm):
         """Gradient function evaluator.
 
         Calculates the gradients of the objective and constraint functions at
@@ -242,7 +246,8 @@ class Evaluator3(CustomFunctionEvaluator):
     :type CustomFunctionEvaluator: CustomFunctionEvaluator
     """
 
-    def fcnvmc1(self, n, m, x, ifail):
+    @staticmethod
+    def fcnvmc1(n, m, x, ifail):
         """Function evaluator.
 
 
@@ -265,7 +270,8 @@ def fcnvmc1(self, n, m, x, ifail):
 
         return objf, conf
 
-    def fcnvmc2(self, n, m, x, lcnorm):
+    @staticmethod
+    def fcnvmc2(n, m, x, lcnorm):
         """Gradient function evaluator.
 
         Calculates the gradients of the objective and constraint functions at
@@ -303,7 +309,8 @@ class Evaluator4(CustomFunctionEvaluator):
     :type CustomFunctionEvaluator: CustomFunctionEvaluator
     """
 
-    def fcnvmc1(self, n, m, x, ifail):
+    @staticmethod
+    def fcnvmc1(n, m, x, ifail):
         """Function evaluator.
 
         Calculates the objective and constraint functions at the
@@ -325,7 +332,8 @@ def fcnvmc1(self, n, m, x, ifail):
 
         return objf, conf
 
-    def fcnvmc2(self, n, m, x, lcnorm):
+    @staticmethod
+    def fcnvmc2(n, m, x, lcnorm):
         """Gradient function evaluator.
 
         Calculates the gradients of the objective and constraint functions at
@@ -358,7 +366,8 @@ class Evaluator5(CustomFunctionEvaluator):
     :type CustomFunctionEvaluator: CustomFunctionEvaluator
     """
 
-    def fcnvmc1(self, n, m, x, ifail):
+    @staticmethod
+    def fcnvmc1(n, m, x, ifail):
         """Function evaluator.
 
         Calculates the objective and constraint functions at the
@@ -380,7 +389,8 @@ def fcnvmc1(self, n, m, x, ifail):
 
         return objf, conf
 
-    def fcnvmc2(self, n, m, x, lcnorm):
+    @staticmethod
+    def fcnvmc2(n, m, x, lcnorm):
         """Gradient function evaluator.
 
         Calculates the gradients of the objective and constraint functions at
diff --git a/tests/regression/regression_test_assets.py b/tests/regression/regression_test_assets.py
index 3f63eb0128..ee0431c63d 100644
--- a/tests/regression/regression_test_assets.py
+++ b/tests/regression/regression_test_assets.py
@@ -82,7 +82,8 @@ def get_reference_mfile(self, scenario_name: str, target_hash: str | None = None
 
         return None
 
-    def _git_commit_hashes(self):
+    @classmethod
+    def _git_commit_hashes(cls):
         """Returns the list of commit hashes.
 
         :returns: a list of commit hashes from 'git log'
@@ -125,7 +126,8 @@ def _get_tracked_mfiles(self):
             key=lambda m: self._hashes.index(m.hash),
         )
 
-    def _get_tracked_mfile(self, file: Path):
+    @staticmethod
+    def _get_tracked_mfile(file: Path):
         """Converts JSON data of a file tracked on GitHub into a
         `TrackedMFile`, if appropriate
 
diff --git a/tests/regression/test_process_input_files.py b/tests/regression/test_process_input_files.py
index 0b62666dd7..207a4b70e2 100644
--- a/tests/regression/test_process_input_files.py
+++ b/tests/regression/test_process_input_files.py
@@ -38,7 +38,8 @@
 
 
 class ProcessModelFilter(logging.Filter):
-    def filter(self, record):
+    @staticmethod
+    def filter(record):
         return 0 if record.levelno < logging.CRITICAL else 1
 
 
diff --git a/tests/unit/models/test_divertor.py b/tests/unit/models/test_divertor.py
index 6184c6a864..61aef5e3f9 100644
--- a/tests/unit/models/test_divertor.py
+++ b/tests/unit/models/test_divertor.py
@@ -14,7 +14,8 @@ def divertor(process_models):
 
 
 class TestDivertor:
-    def test_divtart(self, monkeypatch, divertor):
+    @staticmethod
+    def test_divtart(monkeypatch, divertor):
         """Test the divtart subroutine.
 
         Uses test data from the second call of this subroutine by FNSF regression test.
@@ -54,7 +55,8 @@ def test_divtart(self, monkeypatch, divertor):
 
         assert pflux_div_heat_load_mw == pytest.approx(expected_pflux_div_heat_load_mw)
 
-    def test_divwade(self, monkeypatch, divertor):
+    @staticmethod
+    def test_divwade(monkeypatch, divertor):
         """Test the divwade subroutine.
 
         Uses test data from the second call of this subroutine by FNSF regression test.
diff --git a/tests/unit/models/test_structure.py b/tests/unit/models/test_structure.py
index 9b79c3898d..816ee4a626 100644
--- a/tests/unit/models/test_structure.py
+++ b/tests/unit/models/test_structure.py
@@ -16,7 +16,8 @@ def structure():
 
 
 class TestStructure:
-    def test_structure(self, structure):
+    @staticmethod
+    def test_structure(structure):
         """Tests the structure subroutine"""
 
         expected_fncmass = 310716.52923547616
diff --git a/tests/unit/models/test_vacuum.py b/tests/unit/models/test_vacuum.py
index f976f0ef5a..7c869820e2 100644
--- a/tests/unit/models/test_vacuum.py
+++ b/tests/unit/models/test_vacuum.py
@@ -24,7 +24,8 @@ def vacuum_vessel(process_models):
 
 
 class TestVacuum:
-    def test_simple_model(self, monkeypatch, vacuum):
+    @staticmethod
+    def test_simple_model(monkeypatch, vacuum):
         """Tests `vacuum_simple` subroutine.
 
         Values taken from first calling of the model in i_vacuum_pumping regression test.
@@ -57,7 +58,8 @@ def test_simple_model(self, monkeypatch, vacuum):
 
         assert n_iter_vacuum_pumps == pytest.approx(14.082585474801862)
 
-    def test_old_model(self, monkeypatch, vacuum):
+    @staticmethod
+    def test_old_model(monkeypatch, vacuum):
         """Test `vacuum` subroutine.
 
         Values taken from first calling of the model in G-L_Nb-Ti regression test.