Thanks for additional comments.
@Colosseum
Answer is simple - on the one hand last two years or so were to me a period of significant job instability so to speak (with periods of working full-time, part-time and not working at all) which influenced amount of time I could devote to it (especially that drawing things in SB is more economical way of spending time than tourism for example
), and on the other hand, after drawing already quite a number of ships and planes I become relatively fast with it, plus I have a file with elements like roundels, letters (for fuselage codes) etc. or could quickly create new ones from these and additionaly the RAF aircraft usually had identical configuration of camoflage (several variants of them), so I could largely copy-paste the large parts from one plane to another (of the same type).
@Klagldsf
I thought that with engines in place, there wouldn't be much point in showing all (most, actually) versions since most of the major differences would be mostly invisible. (same for Beaufighter)