Government Guidance for Domestic EPC regulations
Find an EPC on the Government Register
Example of a Domestic EPC
The Energy Saving Trust

Example of a Commercial EPC
Government guidance for Commercial EPCs updated Dec 2017
Government guidance Commercial property minimum level of energy efficiency requirements

Green electricty suppliers from Energy Saving Trust:

Good Energy- (https://www.goodenergy.co.uk/our-energy/)
Green Energy UK- (https://www.greenenergyuk.com/OurEnergy)
Ecotricity- (https://www.ecotricity.co.uk/about-ecotricity/our-eco-credentials/our-environmental-footprint)
Octopus Energy- (https://octopus.energy/about-us/)