As far as I know there isn't really a campsite, but you could contact the organisers to check. Most caravans end up in the Brickmakers car park, but you'd need to phone them to check they have space I think. We're doing a Travelodge (Eye Green) for the Saturday night, it's about 6 miles away, but saves pulling the van etc...
Lovely to see you there if you can make it! The main organised Sing is the Boat on the Saturday night, Merek'n'Dary run it.
Hil x