This unit used to be 135 Survey Engineer Regt (TA)
It consisted of four squadrons - HQ & 337 Topo Squadrons based at Ewell; 338 Trig? Squadron based at Southampton and 339 Litho Squadron based at Fulham.

They merged in to 135 Indep Geo Squadron in March 1967 and the writer with many others were made redundant.