FD, (Hi again!) VAT was introduced into the UK in April 1973.
I had a spot check by French Customs at Dieppe (in a G-reg a/c) a few years ago. They surrounded the aircraft on landing, but were very friendly, and spoke good english. They didn't want to see any aircraft documents, but wanted to look at our passports and licences, and examined all our flight bags very thoroughly. They asked how long we were staying in France, and when we said "just for lunch", these appeared to be magic words, and the examination stopped immediately and they left. I never did understand what was going on.