Las Vegas — New fenestration products offer energy, fire and impact ratings; more black profiles; and a fob for automatically opening multislide doors ... also produces uPVC Keystone-brand ...

B&Q sells double-glazed windows and sliding patio doors in both uPVC and white-finished timber. Brands include Velux, Site and Keylite. You can buy double-glazed windows and skylights from Screwfix.