Here is a non-exhaustive list of other organisations with interests in architecture and buildings that you may find useful.
Chiltern Open Air Museum Chiltern Open Air Museum was founded in 1976 with the aim of rescuing threatened buildings. The Museum focuses on vernacular buildings and only accepts buildings those that would otherwise be demolished.
Hertfordshire Building Preservation Trust HBPT acquires and refurbishes properties through agreement with the Local Authorities and building owners and also has a consultancy service.
The Churches Conservation Trust The national body that cares for English churches that are no longer needed for regular worship.