You can reduce the condensation/mould problem by painting the walls and ceiling with a paint additive-
Thermilate.
Thermilate Insulating Paint Additive
The contact between the warm air and the cold wall is dramatically reduced once Thermilate Additive is applied. Therefore the production of water droplets and condensation is dramatically reduced if not totally eliminated.
The room air moisture condenses on a cold surface.
With this paint additive there is a barrier between the air in the room and the cold in the brickwork.
It will reduce condensation.
I have used it on all exterior walls and ceilings.
The walk in cupboard in my kitchen is used to hang dry my laundry. Coated on all sides with this additive, and no ventilation other than the door ajar - no mould.