Damp from roof leak

[Marakith]

Hello -

I'm visiting my Mother in Law over Christmas. Some time ago she had a leak in her roof and my wife arranged for some people to come and repair the flashing around the chimney stack. They seemed reliable and shared a lot of pictures of the repair in progress/ completed with her. But the damp patch on the chimney breast doesn't seem to have dried out in the loft room just below the roof. When the room is heated it shrinks a little, and when not heated it grows again. What do you think would be the best course of action here? (Black markings are where the patch has grown or shrunk and the family has tried to keep track of it)

 

[Participant]

Can you access the area above? First thing I'd do would be to look up there next time it pees it down to see if it's still leaking (I assume it is).

We have a similar issue in a bedroom and the cause is an old gutter on the dormer getting blocked by rubbish and needing replacement.