My experience at the car park was terrible. Entering was no problem, but the exit system is ridiculous and needs to be redesigned. I had paid for 'pre-booked' parking, as had my father who was in a separate vehicle. We both encountered the same confusing system upon attempting to exit. He, unfortunately, was charged an additional 108 pounds which he now has to go through the hassle of reclaiming. I, after much confusion, was eventually able to leave without an extra charge. My problem is with the appearance and instructions on the ticket machine. Although I see that there are instructions written on the machine for those who have pre-paid and those who have not, it is NOT at all clear that you are supposed to sit and wait for someone to answer the call when you press the button. Instead, there is a loud and repeated beeping sound accompanied by a flashing button telling you to press STOP. There needs to be a clearer indication that you are supposed to WAIT, and then give your CODE. When I finally DID get someone on the other end, she was grumpy and unfriendly and there was no apology for the delay. It took ages to get an answer and there was only one other car there. I will probably avoid Luton airport in the future as a result of this. Stanstead has a better parking system.