Just a little attempt to close the thread drift! In June and July 1964 RAF Tangmere hosted the University of London Air Squadron's summer camp. As a non-flying groundpounder member of the Squadron I saw many drops on the airfield, and was aware of Tangmere's ATC being extremely diligent in keeping such operations separate from those of keen undergraduates in Chipmunks. Halnaker windmill was, as I recall, the 'hold' and got quite busy at times.