Caldicot races buggies indoors on friday nights and that's closest to you.
Always a good turnout, most weeks we get around 30-40 drivers at clubnights running 2wd, 4wd and the odd micro. All standards from ex-F1's to complete beginners.
Normally get a good 10-15 minutes open practice, 4-5 heats and a final.
Cheap too
http://www.caldicotrcracers.co.uk/
Or also on Facebook.