They weren’t Parliamentary seats were they? Some localised support for Reform but in the big picture they aren’t doing so well. Not rocket science!
The other 2 Parliamentary by- elections show Farage holding his seat (with no proper opposition) & Labour holding Starmer’s.
He does have a mandate. He is leader of the party elected on a manifesto that said that in this Parliament we would work closer with EU but not rejoin. So that’s up to 2029. It doesn’t preclude conversations about anything!