Whilst not casting aspersions at Bankrupt's take on this, I find that Jeff Howell's article is a load of unmitigated bull. Presumably he was looking for publicity for his column/book. As a plasterer with over 35 years of experience, I've been doing damproofing and tanking for about 25 years. Now damp penetrates three ways: up, down or sideways. Downwards is generally caused by roof defects, leaking pipes, condensation (interstitial or otherwise), guttering problems etc. Lateral penetration is generally caused by retaining walls, cracked plaster/brickwork/blockwork, thickness of render, lack of waterproof chemical in the plaster etc. (Lets not go into hydraulic lime mixes - that's for another day). And finally rising damp. How else can this knowledgeable fellow from The Sunday Telegraph explain that most of the 'perceived' dampness (such as peeling paint/wallpaper, rust stains on nail tops in skirting, creepie crawlies, efflorescence, spalling of bricks/blocks etc) takes place in the bottom metre of the walls. And here I'm talking about houses that have a DPM under the floor. Why did the Victorians put rows of slate about the same height as we now put DPC. To keep the spirits in the underworld?
I use a dampmeter ...... tho' after years of experience anyone can have a very good shot at sizing up the situation. In all that time, I've had one callback! Which I was able to rectify in little over an hour. In olden times they used imporous stones at the bottom of walls. Aesthetics? Hardly so!
Finally, I'd advise the OP to get a reputable damp company to sort the problem. 25/30 years guarantee is the norm. I'm sure if there were lots of follow-up problems the insurers would pull the plug on this very valuable service.