@blackj what I did over the winter was turn my radiator temp down at the boiler to 45*C. If you can run your boiler at between 40 and 50*C during the winter your house will be fine, just as it is, for an air source heat pump.
I know you love the SNP government ? but if your insulation is not up to scratch they will help with the cost of that too.
The only person who got all his work done by Friday was Robinson Crusoe.
Anything i post over three lines long please assume it is an article lol.