I think there would be interest around the Heathrow area, West London, there are indoor tracks & outside not far, Taplow, Farnham, Watford = a good body of racers in the area.
Tony Truman ran PDA in Bicester see:
http://www.oople.com/forums/forumdisplay.php?f=93
or google Proline Dirt Arena to find youtube stuff. I am sure if you pm him (Teddy Truman) he can give you advice, I would be tempted to pm Lee Martin as well, helped set up PDA and dirt practice would appeal to him, he's just up the M4 (both busy this weekend at area 51)
Tyres on 10th would be proline hole shots or something American.
PDA was soil/clay damped down, not dusty and good to race on. DO IT
Edit: 'What is a good size track for 1/10th-1/16th (width/length) and could i get it in a 150sqm area' I think that's the question that needs looking at, difficult to visualise, track needs to be over 2meters wide, ideal 3 meters, spots for marshals etc