In the Netherlands, "hybrid" heat pumps that switch to gas for hot running water (no hot water tank necessary), and for heating during the coldest few days of winter (no radiator upgrade necessary), will become mandatory for existing builds by 2026. Considering the similarities between British and Dutch post-war home construction (we're the only two countries who ever thought terraces were a good idea), climates and gas infrastructure, I'd be surprised if this wasn't a viable option for British homes.