I don't think I really dealt with this the best way. After due consideration I have decided to call the puzzle solved and award one point each to shamrock and willie mccrum.
It is a known fact that shamrock has good knowledge of motor sport, and he would almost certainly have solved the puzzle in a very short time so no outside assistance would have been needed. Willie got the correct answer, not knowing that whilst his fingers were typing the answer, I was putting a lock in place.