It’s strange that it’s just your rear windows that are suffering from condensation and not the front ones as well. Have you checked that the carpets in the back of your car aren’t damp? Probably also worth checking in the spare wheel well to make sure it’s dry. Did your rear seat get wet (and if so, is it still damp) when your headlining in the rear was wet? Do you have or have you had any damp coats in the car - in the boot or on the back seat? It you do find damp in the rear passenger compartment, you may have a faulty door seal, or if you’ve got damp in the boot, a faulty tailgate seal or faulty seal around one of the rear light clusters.
I seem to remember some time ago that a mk7 owner on one of the Golf forums (sorry, cant remember which forum or how long ago) had an issue with water getting in the boot around one of the tailgate hinges where it’s bolted to the bodywork above the hatch opening so probably worth checking around the tailgate hinges too.
If everything is dry in the car, as others have said, keep your a/c on 24/7. I keep mine on auto all year round and don’t have any issues with condensation.