Just as an aside, I was on the redevelopment site rececently when I saw a boffin carrying all sorts of equipment. Transpired he was testing for radiation. He went on to tell me that after WWII a lot of aircraft were broken up at West Drayton, and he believed there were lots of cockpit instruments buried there. Apparantly, the dials were luminous which makes them radioactive. He went on to tell me that back-lit dials could be seen by the Luftwaffe fighter pilots. Don't know how true all this is, but it interested me ! Have a nice day.