The doors caught the eye of many visitors, but also on the stand were timber windows and doors, aluminium-clad windows, and a hefty oak folding door.

"We’re showing what we can do with timber windows and doors," said marketing director Mike Tattam.

And that included a triple-glazed, insulated mortice and tenon door which boasted a U-value of 0.8, and an aluminium-clad tilt and turn window with a U-value of 0.7.

"We used to be known for doors but we’ve manufactured windows for three years and it’s a growth market for us. It’s now the largest part – 51% – of our business," said Mr Tattam.

The company is based in Glasgow but 80% of its business in the south-east England and ranges from social housing to top-end self-build orders.

"We also do bespoke work that’s out of the norm, which we can do because our team are qualified joiners," said Mr Tattam.

Russell also provides an installation service. "That allows us to handle the installation more quickly, and having our own installers safeguards our reputation and the product," said Mr Tattam.