I think soulweavers idea of a county court against them for the money is the best idea mate. Theres absolutley no way a judge would award in their favour if the work wasn't done properly.

I'm unsure why the Trading Standards would have said that they couldn't get involved? Surely if you pay a mechanic to do a job and its not done properly, you should either take it back and get it done or get some money back? I'd contact the TS again if you can..

There's plenty of ways to fook em over, tip the VAT man off that they've been bragging down the pub about all the cash work they do? Tell Trading Standards they've been abusing heir consumer license? Ring the police and tell them they're into som dodgy sh!t?

Failing that, I'll come down and have a go at your "usual method of problem solving" for you