mechanic wrote:
We have a problem with pressure loss in our central heating system.
Topping up each day and loosing 1bar or so in a matter of hours
shows something is wrong. Brit. Gas have said there must be a leak
and they've got to the stage of suggesting taking up flooring to
inspect pipes and junctions. This is getting expensive and
disruptive! BG have a £1000 limit on their part of repair and making
good costs. Have people tried:

http://www.adileakdetection.co.uk/le...tion-services/
http://www.leakdetectionspecialists....erty-leaks.htm
http://www.leakbusters.net/
(There are others)

Any experience with one of these companies? Pin-pointing the leak
position may save money in the long term, even though the survey
will cost a few hundred pounds. I've yet to explore the home
insurance angle to reclaim some costs.

Have you checked that the pressure relief valve is seating properly?
A common cause of pressure loss. Normally just turn the knob a few times
with the system pressurised to clear any crud from the seat.