Ex Whirlwind aircrew seem to be a bit thin on the ground don't they
A suggestion for you BlueSky is to go to the
Gaining An R.A.F Pilots Brevet In WW11 thread in the Mil forum and send a PM to cliffnemo.
The available Very colours would have been the same standard issue throughout the RAF at that time, and he may recall what they were or suggest someone who might know.