All I can say is watch out.

I had a similiar problem 20 years ago when I bought the house that I
am still in.

Surveyor for building society came out and said I had rising damp, in
2 areas of the house, that needed looking into. But they still gave me
the loan.

I had a Dampproofing company out who checked all the walls for
moisture, and said they all wanted treating at £???? thousand pounds,
plaster, skirting off etc.

My dad, advised that there was nothing wrong with with the DPC, as
there was 2 courses of blue bricks and nothing can beat that.

The bottom line was

Area Nos 1 -

Rainwater downpipe was blocked up with moss etc, and the rainwater was
building up in the downpipe backing up to the guttering, and then
overflowing down the wall. New guttering and downpipe and a cleanout
solved that problem.

Area Nos 2 -

Cast Iron soil pipe from upstairs toilet was cracked at the back of
the pipe. Water when flusing sprayed all over the wall. New soil pipe
solved the problem.

These problems must have been occuring for over 10 years, but why did
the dampproof company say all the walls needed doing ??

Well all I can say, is the house had not been lived in for approx 1
year, whilst probate was going thru. Thus no heating was on. The
previous owners were OAP's and only lived and heated one room.

I have lived here for over 20 years now, and have had no rising damp.

But then again this is only my personal experience.