Log a landlord fuel that contradicts the heating archetype's natural fuel 🟥

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/repositories/property/test_landlord_override_overlays.py

@@ -6,9 +6,16 @@ that fold onto the lodged EPC — per component, partial, skipping unmapped rows
 
 from __future__ import annotations
 
+import logging
+
+import pytest
+
 from datatypes.epc.domain.epc_property_data import BuildingPartIdentifier
 from domain.modelling.scoring.overlay_applicator import apply_simulations
-from repositories.property.landlord_override_overlays import overlays_from
+from repositories.property.landlord_override_overlays import (
+    flag_fuel_mismatch,
+    overlays_from,
+)
 from repositories.property.property_overrides_reader import (
     ResolvedPropertyOverride,
     ResolvedPropertyOverrides,
@@ -171,3 +178,26 @@ def test_main_fuel_override_wins_over_a_heating_archetype_natural_fuel() -> None
 
     # Assert — the explicit fuel (smokeless coal 15) wins over the coal default.
     assert result.sap_heating.main_heating_details[0].main_fuel_type == 15
+
+
+def test_a_fuel_override_contradicting_the_heating_archetype_is_logged(
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    # An electric room heater is unambiguously electricity; a "mains gas" main_fuel
+    # override contradicts it (a different fuel family). The override still wins
+    # (ADR-0041), but the implausibility is logged for later review — not raised.
+    overrides = ResolvedPropertyOverrides(
+        rows=(
+            ResolvedPropertyOverride(
+                "main_heating_system", 0, "Electric room heaters"
+            ),
+            ResolvedPropertyOverride("main_fuel", 0, "mains gas"),
+        )
+    )
+
+    # Act
+    with caplog.at_level(logging.WARNING):
+        flag_fuel_mismatch(overrides)
+
+    # Assert
+    assert any("fuel" in r.message.lower() for r in caplog.records)