I use Dave Carter. He did most of the workshop work at Speedwell Motorcycles in Fishponds before it closed down a couple of years ago. Now running his own workshop and doing really good work at very reasonable rates. He can also collect with van. Good mechanic and a very friendly guy too. Highly recommended.
His workshop is at the top of Kingswood, near the ring road.
http://www.carterbikes.co.uk/