Tesco is about a five minute drive away, I will take food for the first day and then do a Tesco run the next day after breakfast. Their are barrier gates at the main entrance so make sure that you get a key card from one of the coordinators before you go out or you will be charged for parking.
As it will be the end of August it may get cold at night so it is best to take plenty of bedding both to keep the cold out from the ground and on top of you, also get ready for bed while it is still light and then put some clothes on over the top.
If you are going to do a lot of camping, have room in the car then I and a few others would recommend the Coleman extreme coolbox, although they are not cheap they are very good.
You can park with your tent, just be careful not to block anyone in as most of us will need to go out at some point.