Are you sure that shot was taken in August? I know, b&w undersides were used up until early june, and then later in December, but AFAIK during the BoB 92 squad had egg-green/blue undersides:
I just checked the Osprey Spitfire MKI/II aces book, and I was right. QJ-P was Brian Kingcome's plane, and the markings you're talking about were applied in late November. On the same book it's clearly visible that in August 1940 they didn't have night white undersides (The planes that is )