Central heating a go-go [Lurks]

When we returned from holidays to South Africa, the transition of 35C in Cape Town to 3C in London was a hard crash back to the dreary, wet and cold reality of the British Isles. To make matters exponentially worse, as soon as we got home our boiler packed up. It's an older sort that uses a pilot light and there's a problem where it blows it out and refuses to relight.
We've had this problem before and had some general servicing but it was made clear to us that it is on the way out. We weren't looking forward to the replacement job but by God, we need heating and need it now.
I did find out something interesting while doing boiler-replacement research (which is not as much fun as other forms of Internet research I might be doing...) and that is that as of April 2005, an amendment to the Part L Building Regulations will come into force which stipulates that all new boilers must be of the high efficiency condensing type. Interesting, we like high efficiency being the closet greenies that we are and so I looked into it.
Yer regular old gas-fired combination boiler that most of us here in Blighty use to survive the long and terrible winter, burns gas to heat water. Surprised? You learn something every day on ed.coM! Okay... you may have noticed the jet of hot exhaust gasses chucked out the side of your house. This is mostly super hot water vapour and carbon dioxide. You can steal some extra energy from the gas burning by using those exhaust gasses a little more efficiently, say passing them through some longer metal pipes etc, before chucking them out the side.
This does, however, present a bit of a bind. You see if you keep the exhaust gasses until they cool down a bit, the water vapour will condense. Not by itself a huge problem, although it means condensing boilers need to be plumbed in because a fair bit of water comes out of them, but the water vapour combines with other exhaust products and generates a sort of corrosive liquid that would make short work of ordinary metals. So the condensing bit has to be made of sturdier stuff and that carries with it a bit of a price hike. We're talking about an extra 200 quid on the cost of a boiler as we found.
However if you nip over to boilers.org.uk (you're all hot and bothered now aren't you?), you find that you save 200 odd nicker a year in fuel. At least. So that's not a big put off and that's a lot of extra gas you didn't have to burn.
The other side effect is that once the water has condensed, it's basically a cloud and so you get a big warm cloud eject from the boiler rather than the hot air of the old-type (which would dissipate and the water vapour usually wouldn't be visible except on very cold days). Not such a big deal but if you're in a terraced house like us, you've got to consider the folks who live next door.
Hang on, the folks who live next door are council tennents and are probably paying two quid a week rent. Stuff them!
The clowns who converted our house into flats also couldn't be bothered to put in a thermostat so we had to use the human equivalent. IE, you're starting to sweat and so would dash to the boiler cupboard and switch it off. That's a bit crap. The new boiler will not only have a thermostat but also thermostatic valves on three of the key radiators in the bedroom, lounge and my lair. That way they can be turned down when not being used.
Our gas savings with a much more efficient boiler without a pilot light, central thermostat and thermostatic radiator valves should be rather spectacular and we have the added bonus that it will actually work too.
Sadly they found the clowns who did the work used the wrong sort of flue and the gas main is the wrong gauge so my lounge is an absolute building site at present and all this crap is going to cost us three grand to have done. Which is decidedly unwelcome but at least I can feel cosy and know that we've done a little bit to cut our energy usage.