I was pre-paid and in the correct car and car park at the booked time, but the entry system failed to issue a personalised ticket. I contacted help and was told to press for a ticket, which had the correct car registration on it (so the ANPR worked). On exit, a credit card was demanded, so I contacted help again. I found my booking reference and was allowed out. I think that there are 3 issues here: the system should have recognised that I was a pre-pay in the first place; even if it failed I should not have had to contact help twice; I should not have needed the booking reference since the car registration matched.