We have a place that is heated with electric. I wouldn’t touch storage heaters with a barge pole – not that cheap to run and not very controllable.
Electric heaters generally means 1kw in = 1kw heat out and none of them are going to be very cheap to run.
We have simple panel heaters with a thermostat (although I now control them all using a Raspberry Pi which I can also access remotely).
If you’ve got a fireplace rip it out and put a stove in – I know it’s the STW thing to do but it really will make a huge difference and will make it attractive to people looking to rent. Chances are it will do all the main heating.
Put panel heaters in each room and leave it at that.
If you’re feeling adventurous you could look at installing an air to air source heat pump which is what I’m thinking of doing but we’ve also got solar PV and I’d be running it on spare power. A heat pump ‘could’ give you 3kw heat for every 1kw of electricity. It really depends on how much winter use the place is going to get.
So in summary, panel heaters and a stove if you can.
[this is presuming you’ve already done as much insulation as you can]