My 24-hour eggtimer has run out, so I can officially confirm what the cognoscenti had already figured out - it's RAF Manston.
The location of my first-ever "spotter" photo - Spitfire Mk XVI TB752 - with my bike just visible behind the port "chassis" leg. I found the contact print recently and discovered I had carefully written "Spitfire XVI" on the back!
chevvron has declared Open House.