Highly recommend getting a full damp investigation from a specialist as so few surveyors can find the root cause of an issue, and damp is one you can throw grands at without solving if you're not careful! Our initial home survey picked up rising damp and suggested injections -however my dad pointed out this wouldnt necessarily fix the main issue and at best would mask a longer term problem. We found even companies offering damp treatment (DPCs etc) didnt actually give a shit what the cause of the problem is as long as they got work.

I paid just under £400 Inc VAT for a damp investigation after trawling to find a trusted one. They then found out what was actually wrong and it turned out the problem was actually very old, damaged drainage which meant water was standing under the house so really a damp proof course would have been spaffing money for no reason.

For ref I have a 2 bed victorian end terrace so I'm assuming costs for investigation would be close :).