I've had this email from Mark Whitehead - 

"In 1983 I was posted to Military Vehicles Experimental Establishment (MVEE) at Chertsey, later to become Royal Armourment Research & Development Establishment (RARDE) .....There was a post at MVEE/RARDE for an RE Cpl with HGV1 plus track licence also had to be qualified as a diver for the amphib trials. Not many of us."

RETS (Royal Engineers Technical Services)

Info to follow as I receive it from you lot!

Peter Luscombe tells me -" 

For many years the Royal Engineer Technical Services (RETS) worked out of Christchurch. They were not part of RARDE but were independent with their command coming from Long Marston. This unit got amalgamated with 8 Maintenance Advisory Group who also worked at Christchurch but came under the REME Vehicles and Weapons Branch at Chertsey."