try

pipeline/transform/join_epc_pp.py

@@ -21,7 +21,15 @@ from ..utils import (
 pl.Config.set_tbl_cols(-1)
 
 RATING_RANK = {"A": 1, "B": 2, "C": 3, "D": 4, "E": 5, "F": 6, "G": 7}
-MIN_PRICE = 50_000
+# Value-quality floor for price aggregations. A flat nominal floor is a blunt
+# tool against a deflating threshold — £50k was completely normal for a 1990s
+# house, so a 50k floor wrongly discarded ~a third of legitimate 1990s
+# open-market sales (and deleted properties whose only sales were old/cheap),
+# biasing early-year price history upward. 10k recovers the large [10k,50k)
+# band of genuine cheaper sales while still excluding the nominal/junk transfers
+# (£1 etc.). A small tail of real sub-10k sales is still dropped — a deliberate
+# conservative tradeoff to keep clearly-implausible transfers out.
+MIN_PRICE = 10_000
 
 # Plausible construction-year range; band-derived years outside it (e.g. OCR
 # noise like 1012 or 2202) are nulled rather than published.