Had the challenge of flying each of the Varsitys, or should that be Varsities, at ETPS Farnborough in 1955.
I had one flight with an instructor named Jack? Hindle before being let loose with flight test exercises on my own but I had plenty of prior time in Gooney Birds so it wasn't a big deal.
I never did record the letters before the numbers which oddly were 381 and 681. Could I have been mistaken with the first digit although I think there were two in the fleet which also included a Valetta..