We live in a conservation area and want to demolish an outbuilding and then build a single-storey rear extension. Can I make just one householder application?

If your property is not listed you can submit everything, including building a single-storey rear extension, in one application as a Householder Planning Application. In the application, there is a section to complete for demolition within a conservation area. This only needs to be completed if the volume of structure to be demolished exceeds 115 m3.