Hello Stephen
We are experiencing serious condensation on the front window, the other two also show lesser signs of condensation. Over the past few weeks 5 out of the 8 windows began to show signs, depending on the type of weather. Worse in cooler conditions but still there when hot and sunny days. The van has just been brought back from its 1st service!!!
As the van is still under warranty it was reported as a fault and, although the caravan company attempted to get rid of the fault(s) they failed. I refused to leave the service area without this issue being resolved. Very quickly they agreed to order a complete set of new windows! Will take 6-8 weeks, less hopefully. Not a good advert when we are going on holiday. Luckily my persistence(I tend to be like a dog with a bone!) pais off and will get the problem sorted for good. Then we will exchange the van. Will never be happy with it.
We were advised initially, to take out the window plugs and use a hair dryer to get rid of the condensation - didn't work for us, but it may help you if the condition isn't too bad.