I purchased a new sealed DG unit for the kitchen window which was condensated up, £12.50 and a 5 year guarantee, great stuff. First time changing anything like this but it was easy enough with the security tape I got off eBay. The most time was taken scraping off the old tape to make good.
Had a look around the house at the other windows and found four which had units with no security tape/seal on them at all. Looks like previous owners had some unit's changed and the monkeys that replaced them didn't bother with the tape. So I took out these panels and replaced all sealed up as should have been. The two units on the ground floor came out with a bit of a shove. Nice and secure ..... not.
It's no wonder why I could never get some rooms properly warm, it turns out it's the rooms which had DG tape missing. I never would have checked before. I just thought the quality of the uPVC frames was crap and caused draughts.
Hopefully we should have a warmer house this winter!