Protecting yourself when buying double glazed windows
Firstly, deal only with certified & accredited installers from UK trade bodies like FENSA, CERTASS & GGF or DGCOS. These trade bodies vet their members prior to accreditation and continue to do so regularly afterwards.
Secondly, get as many guarantees as you can and get them in writing, the quotation should definitely be in writing as there is no room for dispute if it’s written down. To get free written quotes from properly accredited double glazing installers you should get more information from the GGF
Thirdly, many double glazing companies offer financing for the work, always know your rights about this – there are special regulations and requirements to which the company must adhere and as a little tip, if you can do it, pay any deposits with your credit card as if there is a problem you can raise a dispute and the credit card company then has responsibility to act.