they do, I always like to stay under 2KW, as we know the UK plug can handle that in one it without getting too hot
the 500 W Skirting rad's are fairly low cost to buy and run
maybe try one of them, if its not warm enough, you could get a 2nd to put in the room, even out the heat on 2 sides ( depends on the size of your room, you could just leave it on 24/7 )
https://www.screwfix.com/p/glen-2150...-x-211mm/992hv
500 W costs 14p a hour to run
the 1500 or 1800 W heater would be my choice though
https://www.toolstation.com/airmaste...-heater/p75252
https://www.toolstation.com/airmaste...-heater/p37573
Airmaster are a good brand
its free standing, under 2KW, plug in and feel the warmth