DH knows random stuff, and apparently looked up Thermofilm just a few weeks ago ?? He asked - what is dimensions of the heater?
DH knows random stuff Ok the heater is about 100cm by 50cm. Is that what dimensions is?

Sounds like your panel heater is a convective one. Does it have a thermostat or a dial to set the temperature? Also check on the back of it to see how many Watts it is, the higher the watts the more power it will use but if it has a thermostat it will turn itself on/off to maintain the temperature and not be on all the time (the heater should be able to be lifted off the wall, it is probably on a bracket). I would avoid buying oil heaters as they take a lot of energy just to heat up, where as convective panel heaters are pretty much instant. They can be more expensive upfront to buy but I think for comfort and running costs they are worth it.
We use panel heaters with thermostats (Noirots) in the kids' rooms at night set at about 18 degrees. A 1000W is more than enough for bedroom IMO.
Thanks Dusty DH took it of the wall cos it was only mounted and judging by the sticker on the back we think it's 2400 watts. I don't know if it has a thermostat, but it has a dial from 1 to 6.