diff --git a/tests/repositories/property/test_landlord_override_overlays.py b/tests/repositories/property/test_landlord_override_overlays.py
index e6e60b4e3..37bf4bc19 100644
--- a/tests/repositories/property/test_landlord_override_overlays.py
+++ b/tests/repositories/property/test_landlord_override_overlays.py
@@ -227,6 +227,92 @@ def test_main_heating_system_row_produces_a_heating_overlay() -> None:
     assert overlays[0].heating.sap_main_heating_code == 104
 
 
+def test_band_parsed_from_the_heating_description_sets_the_efficiency_slot() -> None:
+    # Ship-before-FE (parse-on-read): the SEDBUK band is already carried in the
+    # main_heating_system row's original_spreadsheet_description, so the modelling
+    # honours it without waiting for the new boiler_efficiency_band override row.
+    overrides = ResolvedPropertyOverrides(
+        rows=(
+            ResolvedPropertyOverride(
+                "main_heating_system",
+                0,
+                "Gas boiler, regular",
+                original_spreadsheet_description="Boiler: G rated Regular Boiler",
+            ),
+        )
+    )
+
+    overlays = overlays_from(overrides)
+
+    assert len(overlays) == 1
+    assert overlays[0].heating is not None
+    # G-rated gas regular → Table 4b (66, 56), not the condensing 84% default.
+    assert overlays[0].heating.seasonal_efficiency_override_pct == (66.0, 56.0)
+
+
+def test_explicit_band_override_row_wins_over_the_parsed_description() -> None:
+    # Once the FE classifier writes a structured boiler_efficiency_band row, it is
+    # the authority — it wins over the on-read parse of the raw description.
+    overrides = ResolvedPropertyOverrides(
+        rows=(
+            ResolvedPropertyOverride(
+                "main_heating_system",
+                0,
+                "Gas boiler, regular",
+                original_spreadsheet_description="Boiler: G rated Regular Boiler",
+            ),
+            ResolvedPropertyOverride("boiler_efficiency_band", 0, "D"),
+        )
+    )
+
+    overlays = overlays_from(overrides)
+
+    heating = next(o.heating for o in overlays if o.heating is not None)
+    # D wins over the description's G → Table 4b (80, 70).
+    assert heating.seasonal_efficiency_override_pct == (80.0, 70.0)
+
+
+def test_band_repoints_with_the_resolved_fuel_for_an_oil_boiler() -> None:
+    # The band is applied AFTER fuel resolution (ADR-0067): a gas archetype on an
+    # oil main_fuel resolves to the oil boiler, and the band keys off the oil code.
+    overrides = ResolvedPropertyOverrides(
+        rows=(
+            ResolvedPropertyOverride(
+                "main_heating_system",
+                0,
+                "Gas boiler, regular",
+                original_spreadsheet_description="Boiler: D rated Regular Boiler",
+            ),
+            ResolvedPropertyOverride("main_fuel", 0, "oil"),
+        )
+    )
+
+    overlays = overlays_from(overrides)
+
+    heating = next(o.heating for o in overlays if o.heating is not None)
+    assert heating.sap_main_heating_code == 127  # oil regular
+    assert heating.seasonal_efficiency_override_pct == (80.0, 68.0)  # oil D → code 126
+
+
+def test_no_band_information_leaves_the_efficiency_slot_unset() -> None:
+    # A plain boiler description carries no band → no slot → condensing default.
+    overrides = ResolvedPropertyOverrides(
+        rows=(
+            ResolvedPropertyOverride(
+                "main_heating_system",
+                0,
+                "Gas boiler, combi",
+                original_spreadsheet_description="Gas boiler",
+            ),
+        )
+    )
+
+    overlays = overlays_from(overrides)
+
+    heating = next(o.heating for o in overlays if o.heating is not None)
+    assert heating.seasonal_efficiency_override_pct is None
+
+
 def test_unresolvable_rows_are_skipped() -> None:
     # Arrange — an "Unknown" property type and an unmapped wall material.
     overrides = ResolvedPropertyOverrides(