Finding a parking space etc was no problem but when we returned our ticket would not work and the machine kept saying it was no longer valid. I went to the pay machine thinking perhaps we had overstayed as it had taken us a while to get through passport control and collect our luggage. When I put the ticket in the machine it said we owed £168 !!!!!! I pressed the help button and gave my reg number and was told to go back to the barrier and press the button which I did and we were let out the carpark but this was something I could have done without after a flight