McAlpines were UK agents for Piaggio and several P-166s came through Luton. I remember one having to land wheels-up on the grass when they could not get the gear down.
In the first pic I think the C310 in the middle is G-APUF (haven't looked closely). It was three-tone green. I think there may have been another similar colour however.
The HS125 G-AYRR was after John Cunningham landed it (unintentionally!) with the gear retracted. He had the Spanish Minister of Tourism on board and was early so he slowed down but the gear warning horn was annoying him so he pulled the circuit breaker . . . . . John was very polite. After the aircraft came to a halt he said on the RT "I am awfully sorry, I seemed to have made a mess of your runway."
It was a Saturday. On the following Monday he called all his pilots into his office at Hatfield (he was de Havilland's Chief Pilot), told them what he had done and on no account were they to do the same.