"Dave Liquorice" wrote

Does this damp require high levels of ground water, or does it just need
contact with damp soil?

High ground water levels will make it worse and being on top of hill
doesn't mean that the ground water level is low, there are plenty of peat
bogs on tops of hills...

Capillary action will draw water from wetter places to dryer ones.

--
Dave

We are on clay with no evidence of high ground water. Does this change the
prognosis?

Phil