That middle line could mean pretty much anything! Random intervals rather than any sort of methodical testing could mean the surveyor got three elevated readings within 1m^2 of each other in one patch and again in another patch and then inferred the entire wall is damp. I think in your shoes I would explain the results to the EA and request another viewing - go with your own damp meter (they are inexpensive and useful to have anyway - I've had one for years) and give everywhere a good look. Any signs of a problem worthy of immediate rectification will likely be extremely obvious unless it was decorated pretty recently. Even a lick of paint might not mask significant salt staining or even the smell of damp if it is particularly bad.
As fastwunz said above, there are things you can look for if there is an issue, like any underfloor ventilation or overflowing gutters. If it has been mistreated/undermaintained and allowed to be wet for an extended period of time (around downpipes, blocked drains, raised beds against the house etc, you get the idea) you'd likely see spalling of the brickwork or failing mortar (or both) on the external side of the area of concern. If the exterior of the wall has been rendered then even the most innocuous looking cracking in the render could (almost certainly will) be allowing rainwater to penetrate and dwell between the render and the brickwork and this absolutely will lead to dampness inside the house.
As fastwunz said above, there are things you can look for if there is an issue, like any underfloor ventilation or overflowing gutters. If it has been mistreated/undermaintained and allowed to be wet for an extended period of time (around downpipes, blocked drains, raised beds against the house etc, you get the idea) you'd likely see spalling of the brickwork or failing mortar (or both) on the external side of the area of concern. If the exterior of the wall has been rendered then even the most innocuous looking cracking in the render could (almost certainly will) be allowing rainwater to penetrate and dwell between the render and the brickwork and this absolutely will lead to dampness inside the house.