Damp barrier advice help

[Funkyboy]

Hi All,

Is anyone familiar with damp proof membrane systems?
My parents have just had this fitted in their home then plaster board dab and dotted onto it and skimmed.
There is some cutouts for in the plaster board for service utilities and radiator pipes. In these gaps if you touch the plastic membrane it's wet to the touch same for other areas that you can get your fingers under the plaster board gaps.
As the room is full of moisture as guys only finished today I'm thinking it's condensation.
I've put a couple of pictures up of the barrier system. I'm thinking because it's an old house this probably wasn't the best way to stop penetrate damp as now the wall can't breathe.