Another website where you can find some pretty good deals is http://www.bookfhr.com/. Here you can get up to 12% off in 116 UK airports, 15% in 17, 18% in 30 and 25% off in 4 different airport car parks. Also, on this website you won't have to pay an extra fee for using your credit or debit card, but you might have to pay a £6 access fee to the parking once you are at the airport.
