I have to drive to Heathrow in the summer and am trying to book a carpark space, which I'll need for 11 days. What is worrying me is that the official site and Purple Parking (which I've used before at another airport) are both quoting twice as much as a few other comparison sites I've looked at. Our flights are at reasonable times of day and we've no small children/elderly people so really just want the cheapest option and paying £220 instead of £97 is quite a consideration for me. I don't care if it's a bit more time-consuming but I'm worried about being ripped off - should I be? Anyone got any experience of using these sites? Thanks.