In the summer of 2000 (just weeks before Ray's TV appearances as one of the experts for the BoB 60th anniversary) I chanced upon Sky Spy in a local bookshop. Opening a page at random, I chanced upon the words "if you want to travel incognito by bus, do not carry with you a 6 foot long Dornier propellor blade with bullet holes in it."
I bought the book!