I was recently in a situation where I had to replace my oil-fired heating system’s oil tank (it wasn’t double skinned and no longer safe).
It was £2500 to replace the oil tank, or I could opt for £2250 to install a heat pump with the government grant. This included all plumbing, electrical work, installation, and 6 new radiators all over my house.
Honestly to me it seemed like a no-brainer. It’s a tad more expensive to run, but it works really quite well and is a lot less invasive than a big smelly tank of kerosene. I gained another 90cm of width in my garden, it’s actually quieter than the oil boiler, and it doesn’t stink in the summer- win win.
Did you add extra insulation to your house (or was it already more modern?).
Otherwise the heatpump just can't catch up.
And currently I have the opposite problem. The house is too well insulated for the heater (or the heater is too powerful). The heater only runs for a couple of minutes and huts off.