The (experienced) poster on post # 39 was the only person who was prepared to make an estimate BEFORE i said what I had been quoted !! It's amazing how many "wise after the event " and "anti BG" people there are on here !!
I agree BG are not cheap (but then again cheap, in my experience, usually equates to rubbish !), but for 7 hours work, "peace of mind", first class workmanship, and a "life time guarantee" on all the work, I am content !
Again the work I had done (cost £645) was : Offending sections of the cold feed and open vent pipework cut out and replaced, power flush, a Spirotech supplied and fitted and inhibitor added.
Cheers.