But 72's wartime Sqn Bigraph was "RN" and not "RA"! (Yes, of course I see what they've done and why)
And it certainly avoids confusion. One once saw an American publication - can't remember what - with photos of some 72 Sqn Spitfires, complete with RN markings. Problem was, the picture was captioned as "British Royal Navy Spitfires from the Fleet Air Arm". Doh!