This is such a common problem, but there can be a number of causes. You need to make sure when you instruct your damp surveyor, that you ask specific questions. In this video, I go through the typical causes of rising damp, along with telling you which British Standards, and questions you need answered to get the correct damp diagnosis.
One of the most common cause of rising damp is also because of drain defects. Have you had a CCTV drain survey as part of you rising damp elimination process? I offer CCTV drain surveys, along with quantitative moisture analysis following guidance in BRE Digest 245.