Had a leaky bonded window. Looked into removing it myself but national windscreens will remove and re-bond it for 70 quid. Worth the money I reckon. They also showed me the difference between the kit sealant I used and the product they use. The difference in quality is night and day. I bought my windows from kiravans with the bonding kit. The windows are good quality but the sealant they supply is called winbond. Won't be using that in future and for the sake of a few quid, peace of mind and a gaurentee its probably worth getting windows done professionally. Hope this is of some help to someone.