Pre-booked a long stay car park, on arrival signage should be improved. Took a ticket to open the barrier. would have expected the barrier to open automatically as pre-booked. On departure the exit barrier did not recognise my number plate so I inserted my ticket. The screen informed that a fee of £155.00 was due for parking. Seem like ANPR was not working. Knowing it was an error I pressed the call button. A very helpful gentleman answered asking me for my registration number, I gave it only to be told it was not on his system. he subsequently asked for my booking reference number which did identify me. He then had to open the barrier for me. Out at last!