A couple of links that may be of interest:
Geoff, this one's for you http://www.energysavingtrust.org.uk/About-us/Press-releases/Archived-press-releases/New-energy-saving-advice-service-to-be-launched
And this is from DECC's website, it is some market research investigating how people might view the prospect of taking out a green deal:http://www.decc.gov.uk/assets/decc/11/consultation/green-deal/3592-green-deal-household-model-assumptions.pdf
Th paper describes itself thus: "In order to understand the... likelihood of success of this innovative policy on the uptake of energy efficiency measures, DECC has commissioned an extensive consumer survey to assess the attitudes of consumers ... Element Energy and Cambridge Architectural Research were subsequently commissioned to produce a model of consumer uptake under the Green Deal, based on the survey results."
One sentence in this report stood out for me:
"It should be noted that the overall attractiveness of the package [of energy saving measures] remains negative (even taking into account the energy savings) for most house types."
In short, as things stand with the Green Deal, most people won't want one, and DECC knows it. Or at least having read this through a few times, that's what it looks like to me. Oddly, this finding does not seem to have been mentioned much.
I have been reading around on this quite a lot, and there does seem to be a massive gulf between what on the one hand DECC is telling itself they can persuade people to do, and on the other, the likely reality (based on what people have signed up to in the past (under other schemes, pilots, etc) and/or what they say they would do in future).
I really don't think the Green Deal (as opposed to the ECO) is going to be at all popular. In particular, all the market research makes it clear that if people do take out a green deal at all, they will tend only to go for 5 or 10 years on the whole, at least avoiding the worst of the interest payments.
However, many businesses are being hyped into investing in Green Deal accreditation, training, etc. Some of them will be able to make a return on this, via delivering the subsidised "Energy Company Obligation" aspects of the Green Deal, not all of which oblige the householder to take out a loan, and a few of which might even be half-decent jobs (possibly). However, as you fear, there is I think the spectre of desperate companies mis-selling Green Deals on the doorstep to vulnerable householders, when a more reputable business stream fails to materialise.
Ebs, I know at least a couple of consumer organsations, Which? and Consumer Focus, have this issue in their sights and it might be worth looking at what they have to say - I recollect that possibly CAB has its eye on this too. It may well be that one or more of these bodies is preparing some sort of "questions to ask before you agree to a green deal" guidance; if they aren't, you could suggest it, as they know how to write that sort of thing, and probably have a budget! Maybe you should recommend they approach AECB for technical input into advice about how plausible the "savings" claims might be.
I am in the process of writing an (extremely long) review of the Green Deal as I see it, which I hope will be available either here on the forum, or elsewhere on AECB.net. It isn't going to be a rabble-rousing document, but does contain a lot of references many of which do back up some of the points you are making. I don't represent the AECB (just an occasional hired hand!) but if you weren't at the conference, I can tell you that every time anyone mentioned the Green Deal a groan went round the room, so you are hardly alone among members!