Caldicot is a good shout...much fun racing there...racers of all skill levels so you'd fit right in, and good fun indoor offroad tracks
And also in the South West, in Weston-super-Mare, the new WORM track might be a possibility too as we will do guest access!
Although perfectly driveable now, we're due to completely cover the whole thing in better astro mid July, and I can organise access depending on the dates...PM me here if your interested and we'll see what we can do!
If you do pull this off you should keep a diary...and post pics of all the places you visit...it would be a good little bit of PR for the clubs you visit