Nothing quite so complicated as different units Airsmiles!
I served with the Beaver Flight in NI from 76 to 78 and was there when the spinners were painted. The OC at the time had managed to take the wrong a/c on a sortie, so he needed something to help him recognise which aeroplane was which. All we had to say to him after that was, " the red one sir", or "the yellow one boss"!! Made life easier for all concerned.
He was a cracking boss, as were all the OCs during my time with the unit. It was one of the best tours of my time in the mob. Great blokes and a great aircraft, except when the starter was u/s and we had to hand crank the engine!
BM