u/Ok-Bet-4696

We went sale agreed on a house around 4 August for €366k. It was advertised as BER C3, but we’ve now discovered that a new BER issued on 16 August rates it G. The estate agent is investigating, but we’re obviously very concerned given the potential cost of upgrading it.
Has anyone been in a similar situation where the BER changed significantly after going sale agreed? What did you do, and did you renegotiate the price? Any advice would be appreciated!