Unless things have changed then the gas boiler ban will only apply to new homes - heat pumps and other alternatives need homes to be very well insulated to modern standards to work effectively and lots of older houses will never be able to reach that standard. Heat pumps need outside space which many homes don't have.
"Will the gas boiler ban apply to my home?
If you’re worried about having to ditch your existing oil or gas boiler – don’t be. The gas and oil banner ban in 2025 only applies to newbuild properties. There are no plans to phase out gas boilers in existing homes."
https://www.edfenergy.com/heating/advice/uk-boiler-ban
Boris did want to ban the sale of new gas boilers in the mid 2030s but is now reconsidering:
https://www.ft.com/content/0c69af3e-37cf-4dff-8c46-994dcaeecad7