Here are some links which you might find useful – 

Certass:  https://www.certass.co.uk/

Energy Saving Trust: www.energysavingtrust.org.uk

Neighbourhood Watch: http://www.ourwatch.org.uk

PatioMaster:  http://www.patiomaster.co.uk

Pilkington:  https://www.pilkington.com

The VEKA UK Group: vekauk.com