Sounds like a bit of a chilly conundrum! Check if all the locking points engage properly and that no seals are damaged. Small gaps might cause those pesky drafts. If you're still unsure, pop by the Hadleigh Glass Ipswich showroom. They’ve got loads of knowledgeable folks around who can offer some solid advice and show you proper sealing methods for
uPVC windows Ipswich homeowners commonly use — without any pressure to buy.