EPC Rating D to C: Freeholder Permission & Exemptions

We're considering purchasing a flat with an EPC rating of D. The EPC says it can be made C, but the first step is to provide cavity wall insulation. To do this, I believe we would need the freeholder's permission.

What is the situation regarding the requirement for a rating of C or above from 2025 if the freeholder won't provide this permission?

The freeholder is the local council, so I doubt they will be ready to upgrade the entire estate. At the same time, we would be happy to fund it.

Thanks.

View Related Handbook Page