G'day Tommy, The triangle most likely would place it in an Armoured Corps unit meaning A squadron. The earlier photo maybe also RAAC or on loan to the Inf. unit. Gunbuggies alternated from RAINF to RAAC for many years.
The 16 would also place it in RAAC. 1 for A Sqn and the 6 (from memory) the Anti Armour Troop.
Lacking the A, B etc part of the callsign though by the look of it.
Greg Mac.