Ian, to back up Charlie's post I'm certain it was the square four and not the triple. As I remember, it was a 750 motor and the triple was never made in that capacity.

On the subject of Nigel Rollason, was it not him that was given a Morini prepared by Devimead to ride in the F3 TT in the late 70s? It dropped it's breakfast all over the Mountain Mile in practice and as I'd just bought a 350 Sport, I got a lot of ribbing about that!