I use Heritage in bristol. Never had any problems, been great handling warranty claims with both communications and quality of work, this was a brand new engine installed in 3 days (including ordering parts!). Always kept me in a courtesy car as well without asking.
Don't know of any independents in bristol although I'm sure there are loads. I've had good experiences hence me staying with them. I try to bypass reception... Just deal with servicing or parts (unless you meant the service reception?)
Be interested in other peoples opinions of any good independents though?