What should I look for in Cavity Wall Insulation quote?

We have a 1976 brick house with un-insulated cavity walls. We've had a "bloke from the Council" round offering grants etc and a quote for the insulation.

I've trawled through a few posts on the subject and it seems that there are different fill materials and wondered what the pros and cons of these were? ... and indeed whether the old fears of increased risk of damp penetration were still valid.

Also any tips on what to look out for with the contractors? How do I know they actually fill the cavity properly? If they offer a guarantee, what should I be looking for in the guarantee?

I guess I ought to see if the energy companies will give me a quote too. I just wonder whether there might be some cowboy subcontractors getting in on all the hype and government money sloshing about.

Berkshire Council employees go round peoples houses offering grants? Then give them quotations?
In my experience grant lists are long and hard to get on so take it while you can.

As for the pros and cons, the argument is still ongoing.
My opinion is the cavity is there for a reason so don't fill it with something that 'could' give you problems in the future. The problems being if they don't fill correctly, causing cold spots and damp problems. It can compress under it's own weight causing cold spots and damp problems upstairs. Not to mention they wont fill if you have blocked cavities and it's up to you to foot the bill to clear them out.

Do the sensible thing - buy some slippers and a thick jumper.

Researched it a bit more...its the Royal Borough of Windsor and Maidenhead.... Home Carbon Saver Scheme. A surveyor came round and drilled a couple of holes and poked a telescope thingy inside to look at the cavity and pronounced it ok for the insulation. He then measured up and found we were a bit bigger than the maximum allowed for a 50% grant but we could have it done if we paid extra for the larger amount of wall. He showed me a copy of the 25 year warranty which I grabbed off him and photocopied much to his surprise. Its a 25 year CIGA guarantee. (Cavity Insulation Guarantee Agency). Just hope its better than the NHBC which was as much use as the proverbial chocolate teapot in a previous newbuild house with defective roof. ("NHBC doesn't cover you for leaking roofs"....whole roof had to be replaced eventually)....but I digress.

He also said it was mineral wool, not foam, so i guess from my research thats a good thing.

Its not exactly clear who will do the work as I haven't had any written quotation or contract, and of course until I do, no money will leave my hands .

He was also offering loft insulation on the same half price deal, but as I have already done some lagging and boarding it would be a major excercise to clear that for them to do it. Anyway i plan to do it myself at some stage with much thicker insulation than currently.

My neighbour, who is on disability benefit, was promised a 100% grant for both loft and walls.

This all happened before Gordon Brown announced all these wonderful government grants for insulation grants (in liu of payments to help with big fuel bills.) ...except you never know what timescale these Government promises are.