Sorry. Just read rest of thread and this post is a little late to the party.
There are probably a few people that have said this already (I haven't read the entire thread), but I'd like to add my name to the list of those recommending you get a proper damp survey by an independent timber & damp specialist.
Look for a company that does not do any actual work, but just surveys. This will cost you a couple of hundred quid, but you will get the TRUTH.
If you use a damp contractor, a company that provides free estimates for example, you will NOT be getting an unbiased opinion. You will be getting a quote from someone trying to part you from your hard earned cash and might even be suggesting you do work that not only isn't needed, but could cause further damage.
When I sold my house ealrier this year our buyers' mortgage surveyor used a poxy electrical meter (ignorantly called a damp meter) to test for and find damp. It freaked her, the buyer, out. We paid nearly £300 iirc to get a proper survey done and guess what? No damp!