Huw, ask them, by letter,so that you get a reply in writing, for the reason for being turned down. According to the National Sporting Code of the ACU they HAVE to give you a reason, though , of course, it may not be the true one, despite what it says in the regs, ie that they dont.They should also have notified you within 48 hours, thats 2 days to me and thee, of the closing date of the refusal of entry, but I bet they didnt!!!
They gave me a reason in 2000 for being turned down that I reckon was a load of bull---t but I made sure that I fulfilled their objections the next year.