When it's not cold enough to turn on the central heating but, it's a little chilly, I use one of these?
John Lewis Tower Electric Heater, White
It heats a room up really quickly, has an eco setting and you can set the temperature so it only comes on when the temperature drops below whatever you have set it at. It has a remote control as well.
Definitely look into getting an electric blanket or throw as they are really warm and you don't need to keep them on for hours as they stay warm for ages.
I was looking for the handwarmers which a friend of ours had for golf and couldn't find them but, I did find these. Have you ever used them?
Amazon.co.uk