Condensation
prevent condensation
repair damage
reduce moisture
prevent cold-bridging
open the windows in cold weather (all of them)
suck up the moisture on cold mornings with a vacuum (can we reach?)
fit extractor fan in bedroom (noisy ❌ and expensive)
Run a de-humidifyer in bedroom (noisy and expensive) ❌
leave en-suite door open overnight (or cut a vent into the door) & shut the trickle vent.
Cut inspection hatch to check what insulation has been fitted where, and if there's a systematic issue.
if there is an issue with construction, then remediate it, and repeat on other window.
which window to start on? - Bathroom needs redecorating anyway, and is a) less disruptive, and b) more evidence of damage.
Redecorate
other thoughts
not a year round problem
what damage has been done that we can't see? rotting roof joists?
More work we can package for Fry Bro's to do in one go, the easier it is to engage them.
conclusion... either
A) Adopt moisture reduction methods in cold periods. Redecorate in Spring.
B) Start doing the moisture reduction, Also do the inspection. then do the redecoration.
Later - C) go for one of the ❌ methods of moisture reduction if both the above have been done and we are still having issue.