Is this your business?
Let us down for 3 dates for install, told us was CERTASS approved but membership had lapsed. Once this was resolved, we had a substantial leak 3 months later. I was told i had perhaps left the window open or it was condensation. Drip seal was finally fitted a month later. Leaked again following year and Sealant replaced. Then was told it might be the hinges. Takes forever to reply, takes weeks/months for repairs. Beware it’s only the frame that’s 10 year guaranteed: apparently installation, hinges, sealant etc all 1 year so when your window leaks that’s what you’ll be met with! Pay cheap, pay twice, don’t bother.