I've not got central heating, so I've always relied upon various forms of electric heaters. Like Gingejbee, I've come to the conclusion that oil-filled radiators are the best for me. (I believe that the newer 'oil free' versions are meant to be even better but they're also ruddy expensive).
After many year's service, my cheapy from Aldi (or was it Lidl?) packed up earlier this winter and I invested in the second one down on this page, from Machine Mart (who've got stores in most parts of the country):
https://www.machinemart.co.uk/c/oil-filled-radiators/
It's an excellent product and I can thoroughly recommend it (unless, of course, real portability is important to you - I certainly wouldn't want to lug it up and down stairs!)