I gave you the wrong phone number. Try 01293-567171.
I don't know the chap, but if they are cleared on a Super Cub in the UK you shouldn't have a problem. I'm assuming however from the use of the term STC that they're probably cleared in the US which doesn't give automatic cross-approval to the UK.
May all seem a bit silly, but me and my profession are a bit like Keef's. We've a fair bit of flexibility in the interpretation of the word, but not actually allowed to re-write it - that comes from a higher authority. I do however sincerely hope that Keef's higher authority is better informed than mine
G