diff --git a/pyproject.toml b/pyproject.toml
index f15f56ee25..83dcb9ca2e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -146,4 +146,11 @@ lint.select = [
     "F",    # pyflakes rules - https://beta.ruff.rs/docs/rules/#pyflakes-f
     "W",    # pycodestyle warnings - https://beta.ruff.rs/docs/rules/#warning-w
     "I001", # isort
+    "SLF",  # self - https://docs.astral.sh/ruff/settings/#lintflake8-self
 ]
+
+[tool.ruff.lint.per-file-ignores]
+# By default, private member access is allowed in tests
+# See https://github.com/DiamondLightSource/python-copier-template/issues/154
+# Remove this line to forbid private member access in tests
+"tests/**/*" = ["SLF001"]
diff --git a/src/ophyd_async/core/_detector.py b/src/ophyd_async/core/_detector.py
index cdc9fb324e..b3f9e53ca9 100644
--- a/src/ophyd_async/core/_detector.py
+++ b/src/ophyd_async/core/_detector.py
@@ -212,7 +212,7 @@ async def _check_config_sigs(self):
                 await signal.get_value()
             except NotImplementedError:
                 raise Exception(
-                    f"config signal {signal._name} must be connected before it is "
+                    f"config signal {signal.name} must be connected before it is "
                     + "passed to the detector"
                 )
 
diff --git a/src/ophyd_async/core/_mock_signal_utils.py b/src/ophyd_async/core/_mock_signal_utils.py
index 7026b4e842..767ebfa125 100644
--- a/src/ophyd_async/core/_mock_signal_utils.py
+++ b/src/ophyd_async/core/_mock_signal_utils.py
@@ -8,11 +8,12 @@
 
 
 def _get_mock_signal_backend(signal: Signal) -> MockSignalBackend:
-    assert isinstance(signal._backend, MockSignalBackend), (
+    backend = signal._backend  # noqa:SLF001
+    assert isinstance(backend, MockSignalBackend), (
         "Expected to receive a `MockSignalBackend`, instead "
-        f" received {type(signal._backend)}. "
+        f" received {type(backend)}. "
     )
-    return signal._backend
+    return backend
 
 
 def set_mock_value(signal: Signal[T], value: T):
diff --git a/tests/core/test_subset_enum.py b/tests/core/test_subset_enum.py
index dfdc7416dd..41af248aac 100644
--- a/tests/core/test_subset_enum.py
+++ b/tests/core/test_subset_enum.py
@@ -6,7 +6,7 @@
 from ophyd_async.core import SubsetEnum
 from ophyd_async.epics.signal import epics_signal_rw
 
-# I think we want to allow these as calling these is only needed for tests?
+# Allow these imports from private modules for tests
 from ophyd_async.epics.signal._aioca import make_converter as aioca_make_converter
 from ophyd_async.epics.signal._p4p import make_converter as p4p_make_converter
 
diff --git a/tests/fastcs/panda/test_panda_connect.py b/tests/fastcs/panda/test_panda_connect.py
index d5d0900b3b..2685f3c66c 100644
--- a/tests/fastcs/panda/test_panda_connect.py
+++ b/tests/fastcs/panda/test_panda_connect.py
@@ -14,7 +14,7 @@
     NotConnected,
 )
 from ophyd_async.epics.pvi import create_children_from_annotations, fill_pvi_entries
-from ophyd_async.epics.pvi._pvi import _PVIEntry  # Allow as edge case for typing
+from ophyd_async.epics.pvi._pvi import _PVIEntry  # noqa
 from ophyd_async.fastcs.panda import (
     PcapBlock,
     PulseBlock,