Hi, Thirty years in the RAF and I have never seen an RAF badge on a a red beret! Nor on any other Army head dress for that matter. That said, whilst in the Falklands running a forward operating base (FOB) and helicopter refueling point at Goose Green with the Royal Scots, I did see attached Army personnel wearing the tam o shanta (is that how you spell it?) but with their own cap badges. I was tempted to try it myself but as I was not actually attched to the regiment, decided aaginst it. Dress Regulation for the Royal Air Force specifically preclude the mixiing and wearing of "other services" insignia and uniform etc. without specific MOD (UK) Air authority. That said, if an Army unit or field commander wanted all attached personnel, to include RAF, to wear a specific item of dress or insignia then I guess that it would happen. In several publications, I have seen RAF personnel weraing un official combinations. For example, an RAF Regiment senior officer wearing a US Army Div patch on his BD jacket sleave and an Army full colonel wearing both army BD and insignia but also wearing an RAF Observer brevet and RAF Regiment mudguards. So, in my 30 years I did not actually see anyone wearing a red, or indeed, any other colour beret, it would not come as any surprise to hear that it did happen and will probably happen again in the future. Better keep this secret or we may see a flurry of "Rare RAF Para Berets" on E Bay!!
Cheers Michael R