Best one I've got I'm afraid, but it shows a little bit more detail on the lettering. Looks to me like they were hand painted in a stylised 'ghoulish' font.
Note the mustard yellow gas detection patch, which had a dull red circle border around it and appeared both sides of the nose.
Also, some of the bomb mission markings look like they may be ice-cream cones which on many sqns indicated a trip to Italy ...
This pic was taken in 1944 when EE139 was part of 550 sqn (formed from 100 sqn when she was HW-R) as BQ-B. I suspect the BBMF may do PA474 as BQ-B as have they not already had HW-A (ND458) "Abel Mabel"?
As for colours - who knows? I wonder how the BBMF research these ...