thanks guys, I managed to find out more and thought I'd feedback
VD/CVD = (Vehicle Depot), Ashchurch, Gloucestershire
ADPCON Automatic Data Processing Convertion (it's details were entered onto an early computer)
RRW was, as you say, The Royal Regiment of Wales,
The Regiment went to Belize from August 1977 until February 1978 and the vehicle was part of the Rear Party (R/Pty) that stayed behind in the UK. It went back to the Regimental establishment on 24th March 1978 when they returned home to Aldershot.
Following that is was in the CVD from 1982 to 1997 before being sold on
thanks for your help!
mike