Entry to the car park and parking was very simple. The courtesy bus to the airport terminal was quick to arrive and the journey took minutes. (Very cheery driver despite the early hour). Minor hiccup on return which has resulted in the rating above. On returning to our car and driving up to the exit barrier, the system did not seem to recognise that we had pre-paid our parking (despite the vehicle registration being printed on the card). We had to buzz for assistance and the issue was quickly resolved but this is the first time we have encountered this problem.