Thanks for the reply.
The alcoves are indeed on an external wall.
Incidently we have just had a damp course company suggest that we spend £6000 on having some sort of bubble wrap stuck on the external wall and then rendered over. If repointing is all that would be required I would hope we could get this done for a good deal less.
The reason we think that it is condensation is that the mould and paint flaking are happening behind units (placed in the alcoves). It also seems to rise up slightly in the corners.
Would you be able to explain how water would get it due to poor pointing? Would we not expect the moitsure to appear frther up the wall?
Thanks again
E.Varnell