How much would it be to camp sat night at stoneleigh with the missus and show sunday in a tin top??

A tent would be more comfortable

in a tent yes.

Is it a tenner each plus 5 quid camping?

tenna a day and £5 for camping it up

According to the poster it's £12 entrance per day on the gate. £10 for advanced ticket sales.
Camping was £5 last year.