If you plan to build and fly a model aircraft in the UK of any type which weighs over 25kg MTOM then it is mandatory (a requirement of the Civil Aviation Authority) that the aircraft is built, inspected and flight proven using the over 25kg scheme operated by the Large Model Association on behalf of the CAA.
The Scheme documentation is being revised and will be published soon.
The Following Locations are approved for flight testing of over 25kg model aircraft in accordance with section 4.8 (8) of Model Aircraft Article 16 Authorisation UAS13534
Langar Model Aircraft Club
Binham Model Flying Site
Cheddar Model Flying Site
LMA North West Model Flying Site