Question Author
Hi Hard@it,
No idea how it has been connected, right or wrong. The only technie bit I do is to attach the cold water supply in hose to the heating return, open both taps (valves) to increase water pressure, then disconnect again, until the next time. Will have to get someone in to look at it yet again to see if what you say could be the problem. I despair at not knowing what the answer is and getting someone in who could tell me anything, and having to accept (believe) whatever they say.
Johnizere,
Having had trouble initially with the zone valve (not working on auto) the system was playing up then with pressure loss. That was fixed, (new zone box) and they did shut all the rads off when testing. All appeared Ok, but then about a week later, the hot water didn't get hot!! That was fixed, but despite being told that the pressure loss must be due to a a leak from the outflow pipe (of which there wasn't) it just continued, until we switched the heating off.
You guys have been very helpful and understanding, I appreciate your time very much, it is very kind of you to try and sort out what the problem could be. I just feel like having it all ripped out and start again, but would that solve the problem, who knows?
Once again thank you. Will post on here if I get any positive results.
n00dles
Leg of Lamb