Thanks for the comments guys!
Here is the prototype Cyclone operated in early 1941 for evaluation and testing before delivery to front line squadrons. This example is painted in early war stock RAF colours before the RBAF developed their own scheme more suited to operations based on the islands, North Africa and around the Mediterranean.
And to post-war, late 1940's...
I've come up with a roundel for the RBAF introduced around 1948 (soon after the maple leaf was adopted in Canada), consisting of three stars in an arc to represent the three main Balearic islands.
I am somewhat tempted to adopt this roundel and change all of my post war aircraft, as I now think that it is more fitting for a Commonwealth Realm, and I can't quite think of a plausible reason for why there would be a transition to the roundel I have been using on modern aircraft which based on the coat of arms. I have struggled to think of a suitable, distinctive and simple symbol for the roundel and settled on the stars as the best solution. The roundels above use WW2 colours, but I've drawn up the standard and low visibility versions using post '47 RAF standards.
What do you guys think?