post some pics of the outside, in your other post you say the left wall has been insulated externally, then it is not condensation, but a leak of some description, as condensation will form on the "cold" wall, for which there appears to be little to none
True, it is forming on the cold wall... I'm just struggling to find a place where it could be coming in from the outside. Its hard to photograph on the outside as it's 3 stories high. The flat roof above is felt and not in great nick. Coping stones around the upstand walls I guess the ingress could be coming in from there...
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