Christian McArdle wrote:
I can smell damp inn the house (and so could he). Also the walls are
painted plaster (no paper). There is one small corner where it has
gone black. Is this mould. No plaster is crumbling but there is white
patches in a few places. Are these the signs I should be looking for.

Probably.

Could the smell simply be the blocked air brick (which I have cleared
now).

This could be the case. It could also be that the channels to the air bricks
act as drains, so you get a layer of smelly stagnant water under your house.

Been there, drained that swamp.

Thats why the very best solution is to lower the ground level outside by
ripping up the alleyway

If this is the case, you should really be looking at either the original
solution of dropping the entire path level (by far the best solution), or
alternatively, preventing water entering the airbricks.

Or as in my mates house, installing a sump, a pump, and a float
valve...if it rains you her this chugging and a stream of **** colored
water spouts out of a pipe into a gutter, I keep thinking he should
disguise it with one of those little statues of little boys that teh
Krauts are so addicted to..