Check out https://www.swipiwi.co.uk/products/internal-wall-insulation/
https://www.winacc.org.uk/
The retrofit standards framework
Approximately 30% of the UK’s carbon emissions come from buildings, with homes responsible for consuming, on average, 35% of all energy. Of the existing 29 million homes in the UK, 19 million have an energy performance certificate (EPC) rating lower than C, and the UK Green Building Council estimates that nearly 29 million homes need to be retrofitted before 2050.
https://www.thenbs.com/knowledge/the-retrofit-standards-framework
https://ukgbc.org/our-work/home-retrofit/
https://www.trustmark.org.uk/homeowner
https://www.gov.uk/find-energy-certificate
https://www.cityoflondon.gov.uk/services/environmental-health/climate-action
See below for information on energy efficiency measures that could save you money and your impact on the environment.
https://docs.google.com/presentation/d/1Jwiv6DK1RYa0ieCuzrEcnrDD6vzJDKHt/edit#slide=id.p1