I've never heard of anything like that before! Must be something to do with their insurance... I've not been to Llandow, it looks 'OK' but tends to kill front left tyres apparently, which makes sense looking at the track layout. Definitely cheap though, and should be a bit more relaxed than the 'proper' circuits.
How far is Anglesey for you? It has more run off than Oulton and will be cheaper, but the track surface is fairly abrasive and hard on tyres if its dry.
I'd say both Anglesey and Oulton have a good mix of fast and slow stuff, you'd enjoy either and as long as the car has fresh fluids it will easily take the 'abuse'. Just be prepared to get the bug