Can we use radiators?
Yes, no problem. The radiator supply temperature is linked to the weather and left running for longer periods, so they will not need to be as hot as with gas or oil where they are turned on in ‘bursts’ of heat. You may also oversize the radiators by 35% or so to take advantage of lower operating temperatures. You don’t need ‘special’ radiators for a heat pump (or aluminium ones either, though of course they work well).