Interesting to see this idea that the word “dull” was dropped throughout the war, when several A.M.O.s (e.g. A.664/42) specified dull red for serials and code letters on day & night bombers, night fighters, ASR, AOP, plus sundry other a/c, while the roundels were just listed as red/white/blue/yellow, and the Keeper of Aircraft and Research Studies, at Hendon, J.M.Bruce, said, in 1976, “Matt Red and Matt blue were used both prior to 1942 and after the war,” which implies that dull shades didn’t start before that date.
Also, the C.O., of Fighter Command, after the dimensions of the fuselage roundels were changed, by A.664/42, asked if would be possible, on night fighters, to drop the white and yellow rings completely, and proposed that the remaining colours should be Dull; doesn’t sound, from that, that the dull shades were already in use, does it?
Edgar