Serious Condensation in bedroom robe/cupboard

[Nicetoseeyoutoseeyounice]

We have just had a new central heating system but no rads in 2 bedrooms as we are having major work done in spring, dormers.
We have swapped one bedroom as it was ice cold even with a heater, the room we have moved to has a built in cupboard, this is not on an outside wall but on the wall adjoining the other bedroom, there is now serious condensation forming, does anyone have any ideas how to temporary solve this.
PLEASE HELP

 

[big-all]

well something is cooling the back like a vent into a chiminie breast

 

[Nicetoseeyoutoseeyounice]

There was a chimney central to the house and this was removed, no gas fire now, would this tell you anything?

 

[big-all]

have you got a picture ??
what height from the floor is the condensation

 

[Nicetoseeyoutoseeyounice]

I will do a diagram and upload to here, before I hit the drawing pad the cupboard is ceiling height, not a high ceiling, also when the room was empty this didn't happen but has happened almost instantly now it is in use, I have been told to leave the cupboard doors open, if this helps I might as well just remove the doors as they will going once work starts, or, is this only going to make matters worse, should the doors be kept shut tight at all times except in use?

 

[big-all]

my thought is there is a vent or perhaps a gap between floor/ceiling and wall allowing airflow from the cavity or roof

my suggestion vent the room when the heating is off
keep the bedroom door firmly shut and the cupboards doors open
do not dry washing towels or other wet things in that room
is there a bathroom nearby??