By Borough
Mansard Loft Conversion Drawings by London Council
Borough-by-borough guidance on mansard loft conversion drawings — local conservation areas, Article 4 directions and validation quirks for each council.
Mansard Loft Conversion Drawings in every borough and neighbourhood
Wandsworth
Hammersmith & Fulham
Westminster
Lewisham
Hounslow
Brent
Tower Hamlets
Hillingdon
Mansard Loft Conversion Drawings guides that apply in every borough
These are the same in all 33 councils, so they are worth reading once rather than borough by borough.