[Graham]

Graham, there's two cars on your list dated 1966, one is the Broadspeed Mini which according to Wiki, was introduced in 1966 which of course is after the cutoff time for this proxy.

The other is the Imp which was first raced shortly after it's introduction 1963.

I think because this is likely to be the only proxy series where those cars could be entered I am going to keep them in as “ invited  cars” they are not likely to present a unfair challenge to the other Mini type cars which this Event was intended.