"The actual position of the dampness" suggests nothing at all about condensation.
Where are the mold spots, and the distinctive shaping of condensation at inside corners?
The OP has noted that the signs occurred after "driving rain".
Attention has been drawn to the very likely possibility of defective flaunching. Incorrect flashing has also been pointed out.
Moisture stained brickwork can be seen on the chimney breast in the loft.
All indicators of moisture penetration - nothing to do with condensation.
The flues might indeed be sulpherising but the pics dont show evidence of it, and sulpherisation doesn't suddenly appear because of a "driving rain" fall.
Where are the mold spots, and the distinctive shaping of condensation at inside corners?
The OP has noted that the signs occurred after "driving rain".
Attention has been drawn to the very likely possibility of defective flaunching. Incorrect flashing has also been pointed out.
Moisture stained brickwork can be seen on the chimney breast in the loft.
All indicators of moisture penetration - nothing to do with condensation.
The flues might indeed be sulpherising but the pics dont show evidence of it, and sulpherisation doesn't suddenly appear because of a "driving rain" fall.