After a bit of help here.
Basically I moved into a new flat about a month ago. it’s one of 4 flats within a house. At a guess i’d say circa 1900 build period.
Basically the bedroom if on first floor level to the rear of the property, with 3 walls exposed to the outside. I have noticed that the bedroom is starting to feel quite damp, there is a patch of damp on the wall to the outside, and some mould has started growing not only on the damp, but also in other areas of the room.
The heating is on for roughly 4 hours a day.
One key point, I’m renting. I told the landlord and he is coming around to look on Monday, but i’m still keen to find out what it could be. Any help would be good thanks.