PMs
What an interesting topic!
Well it would seem having looked at pics of various aircraft that the markings do seem to move from either side of the roundel.
I did some digging and found this:
code development
From the "AMO A154/39 (27 April 1939)" rule it states:
Either forward or aft of the national marking on both sides of the fuselage.
On the other side of the aircraft national marking on both sides of the fuselage
This statement would give RAF Painters a free-for-all on which way round unless the Sqn Boss said something
There was of course an amendment "AMO A926/40 (12 December 1940)"
(vi) Code letters. Code letters are carried by Service types in operational units and operational training units. The two Code letters and one letter to indicate individual aircraft are to be painted in grey paint and placed before and behind the roundels on the fuselage. The code and individual letters may be placed two before and one behind the roundels or vice versa.
The letters are to be 48 in. high and are to be made up of strokes 6 in. in width. Smaller letters are to be used only when the space available on the fuselage makes such a course unavoidable
This sort of hints that its sqn codes first then the aircraft letter but vice versa makes it a painters choice in my mind?
Another slight change in July 1942 A.664
4. Code letters and Special markings.-(i) In addition to national markings, code letters are carried by service types in operational units and operational training units. The two code letters, and one letter to indicate individual aircraft, are to be painted in the appropriate colour and placed before and behind the roundels on the fuselage, except that on Havoc aircraft the aircraft letter is to be placed immediately forward of the leading edge of the main plane and the squadron code letters forward of the roundels. The code and individual letters may be placed two before and one behind the roundels or vice versa. The letters are to be 48 in. high and are to be made up of strokes 6 in. wide. Smaller letters are to be used only when the space available makes such a course unavoidable. These letters are to be painted on by units after receipt of the aircraft from the maintenance group concerned.
The link above is very interesting, have a look and see what you think.
Another question - under what regulation did Sqn Boss' manage to put their own letters on their mount,ie Johnnie Johnson for example.
Enjoy