These are the two LADs which were attached to the two units in question (for 1945):
Serial 642 - No. 42 Light Aid Detachment (Type C), R.C.O.C. - attached to - 29th Armoured Reconnaissance Regiment (The South Alberta Regiment), C.A.C.
Serial 646 - No. 46 Light Aid Detachment (Type B), R.C.O.C. - attached to - 6th Field Park Squadron, R.C.E.