Booking on line was easy and I was very pleasantly surprised with the great price I was offered for a 4 day stay in short term car park. On entry I was very careful to check that my print out did specify 'short term car park' so that I was not faced with an unexpected big bill at the end. The car park was close to the terminal, easy to walk across from and there were plenty of spaces, well marked and the surface was solid, unlike the mid term car park. On return late on Friday night, I drove to the barrier and inserted my ticket. The barrier showed that I owed £144. This was a shock and not a hassle that I wanted to face very late at night when it was cold and icy and having been travelling for many hours. I pressed the button and there was no response. I drove back into the car park to look for another button and to find the telephone number on my confirmation print out. The number I had was open during office hours only. There was no other help point so I went back to the barrier and pressed again. This time I was able to speak with an advisor to whom I gave my ref number and she let me out. Overall this hassle and the panic that I had parked wrongly and owed a large fee or may be trapped in the car park indefinitely were disappointing and spoiled my otherwise excellent experience of parking in short term on a pre-booking basis. I would park here again if pre-booked for the right price but will always check that my registration has been recognised and inform the car park ahead of time if not. This is a basic problem that is inefficient and causes panic for customers unnecessarily. Please try to fix it in future.