I once had a memorable ride in that aircraft with John. I was an instructor at Elstree in 1974/5 and he took me and the then girlfriend (are you still at LATCC Jane?) to Sunderland (I think) to see a ship of his(!)
He constructed an approach on his Decca, which worked out beautifully, and he then took us to the docks, pausing for egg and chips at a disreputable transport café - but they were delicious.
On the way back, the right engine shuddered to a halt, spewing oil (and the oil filter) all over the show. He elected to divert into Luton and carried out an absolutely immaculately flown single-engine approach and landing.
Thereafter, he wandered off and made a phone call (no mobiles then) and about an hour later a limo complete with chauffeur pitched up and transported us to Elstree.
The man was very unassuming - almost an anti-hero. He was clearly a very wealthy bloke but travelled around in a scruffy little Mini.
Happy days!