I had a quick look at my copy of "Fighter Pilot" last evening and it says this (page 51 of the 1969 Pan edition)
"Not long afterwards we made another contribution that was to benefit all our fighter squadrons. While still with Fighter Command, in order to facilitate recognition by our observers on the ground, the undersides of our wings were painted black on one side, white on the other. We considered this to be idiotic, since the German aircraft were duck-egg blue underneath
and very difficult to spot from below, whereas we stood out like flying chequer-boards. So the Bull [Sqn Ldr Halahan - OC 1(F) Sqn] gave orders for the undersides of our aircraft to be painted duck-egg blue, and this too was later adapted for all RAF fighters."
(The "too" refers to 1 Sqn abandoning the "Dowding Spread" where a fighters guns were set to give a wide strike pattern at 400 yards. This was designed to compensate for aiming error and left sufficient lethal density to bring down a bomber. It wasn't so good against fighters though, but Dowding felt that his aircraft wouldn't meet enemy fighters, never mind have to fight them. 400 yards was selected as this was outside the lethal range of a bombers defences.
1 (F) Sqn secretly synchronised their guns on a point 250 yards in front of the aircraft and, as a result, were quite successful against fighters.)
Interestingly, one of the photos in the book (of Hurricane "Z" (N2358)) - shows that the tail markings are worn Great War style, on the rudder itself, not the fin. Also, none of the three photos showing Hurricanes shows Squadron code letters (1 Sqn wore "JX" during tbe Battle of Britain) though, bearing in mind that the book was first published in 1941, these may have
been airbrushed at the behest of the censor.
I haven't been able to find any other comment (other than the "flying chequer-board" one (above)) though am sure I've seen something more critical of the black and white scheme and suggesting that it was responsible for fighter pilot deaths.
P