Ground source heat pumps are expensive and disruptive, ideal for a new build or a major restoration.
We have an air source heat pump as auxiliary bedroom heating - and cooling in summer, otherwise known as an air conditioning unit.
I suspect that for the house heating a larger version may be an option, but it does mean upgrading all the radiators as the circulating water is not as hot as a gas boiler.

Peter,
66, 2016 Porsche Boxster S
No longer driving Tarka, the 2014 Plus 8...