20 Park Hill Harpenden Hertfordshire AL5 3ATReference5/2025/2003Local authoritySt AlbansAddress20 Park Hill Harpenden Hertfordshire AL5 3ATProposalProposed energy efficiency improvements to the existing house; demolition of existing garage and conservatory; erection of a two-storey side extension and a one-storey outbuilding in the rear garden. at 20 Park Hill Harpenden Hertfordshire AL5 3ATStatusRefusedDecision date2026-01-30Validated2025-10-30More planning applications in St Albans