I;m sorry but I'm not going to help much. I bought a house a few years ago and had a very expensive full structural survey done - which came with 'guarantees'. When I came to sell it 18 months later the buyers had the cheap survey done and found 'major damp' in the sitting room and kitchen.

We tried to get the money back from our bank (who we'd paid to get the survey done as part of the mortgage package). But they kept referring us back to the surveyor - and essentially washed their hands of us. I'd been with this bank since I was a child and even my personal banker was aghast. Needless to say we'll NEVER get a mortgage package from them again

. The surveyor had since retired and it was difficult to get any response form him.
We complained to all the relevant ombudsmen - but the long and the short was we got no refund, and had to get the damp fixed before selling. I'm normally quite a chilled person (everyone at dog club thinks I need a rocket up my bum

) - but I was absolutely livid at the whole experience.
Sorry about the rant :), just reading your post brought it all back to me again :)