1House within designated land - Cladding?
On designated land cladding of any part of the exterior of a dwelling (and extensions/ conservatories) with stone, artificial stone, pebble dash, render, timber, plastic or tiles is not permitted development.

On designated land and Sites of Special Scientific Interest the regime for larger single-storey rear extensions (see point 8) which runs until 30 May 2019 does NOT apply.