- http://www.bygonecollection.co.uk/
Fine Sash Window Collection produced by established window manufacterer Masterframe.
- http://www.evolutionwindows.com/
Window manufacturer's offering a large collection of high quality products.
- http://www.fensa.co.uk/
An independant organisation put in place to ensure that complying companies reach a high level of craftsmanship and customer service.
- http://www.thecpa.co.uk/