diff --git a/etl/testing_data/estimate_epc.py b/etl/testing_data/estimate_epc.py
index 2203402a..9ecd7236 100644
--- a/etl/testing_data/estimate_epc.py
+++ b/etl/testing_data/estimate_epc.py
@@ -94,6 +94,8 @@ def app():
             # Perform the same remapping for built-form as in the Property class for this test, in case we get (e.g.)
             # Enclosed End-Terrace
             built_form = BUILT_FORM_REMAP.get(epc["built-form"], epc["built-form"])
+            if (epc["property-type"] == "Maisonette") & (built_form == "Detached"):
+                built_form = ""
 
             estimated_epc = searcher.estimate_epc(
                 property_type=epc["property-type"], built_form=built_form, lmks_to_drop=lmks_to_drop