CWI improper installation. Effect on buildings insurance?

I and a number of neighbours were pursuaded to have CWI installed in 2010, under the Welsh Assembly's Green Energy home improvement grants initiative.

We've now been informed by a canvasser on behalf of a company of "no win, no fee" solicitors, that the work should never have been carried out, as our homes are a non standard build, shown in the industry standards of that time as not suitable for the type of insulation that was installed. To quote from the survey that was carried out

"The installer at the time failed to adhere to many regulations and guidelines to determine the suitability of the Property for cavity wall insulation, and because of their failings to adhere to the relevant regulatios and guidelines, the installer has compromised the integrity of the build."

A group of solicitors, known as "High Street Solicitors" (ATA refundyou.co.uk) are offering to act on a "no win, no fee" basis to seek compensation for the potential issues of resale of the house and also removal of the CWI. We have now been asked to sign documents from a firm Novitas Loans for release of funding to allow the claim to commence. This is, as I understand it, the point of no return. Several of us are being pressured for a signature by Novitas Loans.

However, a number of questions which have been put to the firm that originally approached us remain unanswered,

Primary concern is the affect on our buildings insurance before and after any removal work takes place. I presume that if we initiate the claim, we will have to inform our insurance companies of the changed circumstances (although thankfully, nobody is actually suffering any damp at present). What effect is this likely to have on the insurability of our homes? Additionally, after removal of the CWI, will we be obliged to have it replaced, and if not, what negative effects are there financially.

Finally, if anyone has dealt with these firms and gone through the process, please let me have your thoughts. I cannot find any reviews for either High Street Solicitors group, refundyou.co.uk or Novitas Loans.