There isn't any dedicated HFT clubs in and around Bristol, so if you want to get into the sport be prepared to travel. As Chris has said Furnace Mill is well worth a visit and so is the Quarry http://quarryhunters.co.uk/Quarry/Welcome.html
A great bunch of lads and very helpful. Its just under an hours drive from Bristol (once you know the way
) and they normally hold at least one of the National Series events.
Pay a visit to Glevum in Gloucester sometime http://glevumtsc.co.uk/
, although it doesn't have an HFT course its a good club a few of us are dedicated HFT'ers.
Its a great and challenging sport and well worth getting into.