Five years ago I wrote:
..." kitted out with white shirts and a Thirty Shilling Tailors chalk-striped suit. This natty ensemble was capped by a beret. Now there are heads which suit berets (spherical ones), and plenty more which don't. I looked like Holbein's Henry VIII. I never wore the thing and disposed of it as soon as possible
."...
Never had a Service beret: we thought them appropriate only for the Regt.
In Burma, the accepted alternative to the Cap SD was the Aussie "Bush Hat", which can be screwed up and pushed into any nook or cranny in the cockpit.