I think that's what we're going to have to do - I keep seeing posters saying it's only costing them £5 to maintain 20 degrees and I just don't get it........wails....... We've bled all the radiators, checked boiler pressure etc. The room DM is in is like a double room - half with a really small window and radiator about 120cm long (radiator, not room!), then half with a large window and french doors (all triple glazed though) and a similar sized radiator, but it's north facing. I'm currently investigating gilets and electric overblankets.
The smart meter is showing we've spent about £8 on gas so far today, because I put the heating on timer, not just 'on', so it's a lot less than yesterday, but the room is back down to 17 degrees after the heating went off again at 2pm.