[ZeroGravitas]

This is referred to as "Minimum Energy Efficiency Standards (MEES)" and seems to have been pioneered in the UK and adopted by Netherlands and France and then the EU generally.

[dan-robertson]

IME the people estimating energy efficiency in the UK do not recognise heat pumps and often misclassify them as less efficient systems.

[ZeroGravitas]

I believe the EPC is being updated to fix that and googling suggests it has gone into effect a few months ago.