The GSR Inspector visited this morning. Very nice chap, as helpful as he can be given the remit that GSR have. Can't do anything regarding the unvented cylinder as it's outside the GSR remit but he is qualified on unventeds and did have a look at it and will be noting the problems in his report.
As far as the boiler installation goes, the benchmark really should have been filled out but it is apparently not an absolute requirement. Things that are definitely wrong, and will be going in his report are
* Flue not sealed properly at wall - rattles about a bit in the hole.
* No room thermostat - required by boiler installation manual
* Boiler discharges at low level in the garage. Should be outside.
* No system bypass? Not sure about this one, think he mentioned it. Again a requirement of the boiler installation manual.
The inspector also did a safety check on the gas supply from the meter and noted that there was a leak somewhere. Luckily we traced this to the RangeMaster cooker installed in the kitchen which has now been disconnected from the gas supply which has been capped off in the kitchen, retested and now safe. The cooker now has a lovely "Immediately Dangerous" certificate tied to it.
The gas pipe behind the cooker is not high enough for Building Regs, but apparently this might be ok if the cooker instructions override the regs by specifying a lower height - don't have the manual to check this will download it later when I get home and have a look.
This cooker (as well as the boiler) were tested by the same guy who installed the boiler - we have a Gas Safety Inspection sheet signed by him from March. But apparently the leak could have occured at any time since so we can't really chase him on this.
So, the inspector will be visiting the installer to get his side of the story and we should have the report in "a week or two".
Apparently the GSR can make the original installer rectify the problems with the boiler installation. But I don't think it makes much sense for him to come and just fix up the boiler parts of the system - we'd still have to get someone else in to redo the unvented installation and associated electrics etc. They'd probably have to do some work with the boiler too and so we might as well just get someone we trust to do the whole system. Will have to pay for it ourselves.
Still waiting for the official response to my complaint to the Building Control department, but I have been chatting with someone from there who seems to think the extension should never have been approved with the problems we've discussed here and various other issues (such as no extractor fans in the kitchen or the loo with no window)
Will keep you all updated, thanks for all the help so far.