Calderdale Council's Local Plan sustainability appraisal lists 28 conservation area designation entries, which is 20 distinct areas once the eight boundary extensions are set aside. They include Halifax Town Centre from 1974, Akroydon from 1976, Warley from 1976, People's Park from 1981, Copley from 1983, Savile Park, Skircoat Green and Huddersfield Road East all from 24 October 2005, and Northowram Village from 2011.
The council lists eight Article 4 directions, at Eiffel Street, Birchcliffe Road, Melbourne Street, West Laithe, Hangingroyd Lane, Oldham Road, land at Dukes Cut and land at the rear of 1 to 10 Stocks Gardens.
The council's planning pages add that flats, maisonettes and apartments do not have the same permitted development rights as houses, and that different policies apply in a conservation area. The Savile Park appraisal is blunt about scale: it says dormer windows, turning part of a garden into parking and minor extensions can damage an area if the design or the materials are poor.
We would build a page that names those areas and their designation dates, explains which jobs need permission, and says that you check the address against the conservation boundary and the eight Article 4 directions before you quote.