I do not know, Barry. The car is still trapped in deep storage behind a Saab and a dismantalled 850 sq ft 4m high oak shed. I have no reason to suspect it differs from the period fitted Ducati 250 twin Lawil offered at the time, assuming they did offer one. They certainly did later. The engine is a V twin and looks like a generator, or boat, unit to me. It is too powerful for the chassis, so is limited. I believe Graham Walker removed the governor from his and found it would do around 70 mph. if you were brave enough. The short wheelbase makes it very twitchy at speed.
I believe Crayfords number 5 known. Certainly one 250cc SWB has left the country, I think possibly two. I do not know which models they are that are left, either.
Crayford were, of course, linked to Trojan. Trojan were Lambretta Concessionaires. The mystery, therefore, is who made the Mink, since it would have needed Trojan approval, yet Peter Agg said he knew nothing about it. Strangely there might be a link on the Mink to the Ladybird. It would explain the thinking behind the Mink, and fits in with the notion there was more than one Ladybird. A snowball of snippets, there, coming in on the side.