Tenants rights regarding repairs

FBaby

He said something about when there is warm weather, heat gets trapped behind a curtain or words to that effect, but as its a very thin curtain, I highly doubt it.
It sounded the most ridiculous explanation possible I grant you, his advice was to remove the curtain in the meantime.

The problem though is that someone claiming to be an expert, at least more so than yourself and the landlord is indicating that the problem is with your lifestyle, so it understandable that on this basis, the landlord didn't consider it their obligation to do something about it.

I agree about getting in touch with the landlord themselves. They might have been told by the agency that he didn't need to do anything but actually would want to if doing nothing might mean slow damage to the walls.

PrincessJR

Thank you everyone.

Mr Generous - I'll try to explain

The damp is on the external wall of the upstairs landing (rear of the property). It's a victorian terrace and at some point in the 1980s a flat roof extension was added creating a larger kitchen. When you stand on the landing upstairs and look out of the window onto the garden, directly below is the flat roof of the kitchen extension. I hope that makes sense.