I think Dennis has the answer. Most RAF aircraft were painted on top of a primer that was anything from dark green (zinc based ISTR) to bright yellow (chromium based ?) I suspect that any green showing in the cockpit would be in areas of high chafing from ingress, around frequently operated switches etc. that would be no surprise, my experience of 6 AEF would see an awful lot of ATC cadets scrambling in and out all day, causing the wear and tear to the paintwork, and the occasional boot through the upper mainplane canvas.
Smudge
