Small Welsh met man at Cranwell in late 60s-early 70s. Excellent chap, very dry humour, but sadly cannot remember his name. Whilst teaching Ground School and explaining Buys Ballot's Law, said "I always remember this by the simple way - If you stand in Piccadilly Circus with your back towards the statue of Eros, looking up Regent Street, then Austin Reed is on your left". Ever since then I've had no trouble remembering either the law or the direction.