If it's any help........
I joined the RAF in 1980 having been an Army trained Lieutenant Royal Marines Heli pilot, followed by 3 years as a Flight Lieutenant Heli pilot in SOAF.
As I was joining the RAF as GD(P) I wore RAF wings on all my relevant uniforms. At that time I was told I couldn't wear a Commando Dagger, although I believe they do now.
On the same SERE Course was a former Para Regt Heli pilot, and as he was joining the Fighter Control Branch he was not allowed to wear pilots wings of any description, anywhere.
ERB