Disclaimer: I've never been to the UK outside of Heathrow, but my impression is that climate wise it would be ideal for heat pumps. Cold, but not like COLD COLD.
OK Google says 0F for the record low in London, compared to -15F in NY City.
Housing stock wise: not so much.
Heat pumps seem really good for well insulated modern houses, much of the UK's housing stock is >100years old and pretty drafty.
It's bloody brilliant. Way, way more comfortable than the oil-fired system it replaced. The smart meter looked a bit scary during the cold patch in January but even then, it's coming in cheaper than the oil did and without the scary price variability.
I honestly love it. Getting the size of heat pump right for the property is probably the most critical thing.
But in rural areas it makes no sense. Running a single phase electricity conductor overhead for everything is affordable unless you live somewhere crazy like up a mountain or on your own island, but piped gas, sewage, etc. is just too expensive to justify. This is another reason to favour heat pumps, the heat pump runs off the same electricity as your household appliances, your PC, and your lighting, if you fit solar panels or add a private wind turbine (if you're a hilltop farm latter can make a lot of sense) that's all electricity and it Just Works™.
I have a 17th Century cottage and the folks came and just said that there was no point at all... maybe they were clueless!
So - things have changed.
If you tore the bricks off my home, you'd see a thick layer of insulation, but this place was built in the 21st century and the actual structural loads are internal - floors are cantilevered off the lift shaft in the core while the bricks on the outside are mostly decorative. However if you tried to tear the bricks off my mother's 100+ year old house you'll tear the building down, the loads travel through that brick.
She spends more on utilities in a month than I spend in a year.
My grandmother lived most of her life in a poorly insulated brick terraced house with no central heating - every day she'd get up and light a coal fire in the grate. A lifestyle that belonged more to the 1890s than the 1990s.