Forgive my need to ensure accuracy, but Doug Catto was never the CO of RRC (Royal Rifles of Canada). He was the CO of the Royal Regiment of Canada from July 19, 1942 (replacing G.H. Basher) to August 19, 1942 (technically he was not replaced until August 23, 1942, by A.H. Fraser). D.E. Catto became a PoW at Dieppe on August 19.
I can certainly understand why someone taking notes during the heat of the battle may have mistakenly referred to the Royals (R REGT C) as RRC. However, the RRC was having their own problems, in captivity in Hong Kong, in August 1942, having surrendered to the Japanese on Christmas Day 1941.