Gas fire or radiator???

good question...I would lean towards the gas fire on this one.

The gas fire being flueless has good efficiency however, the vents is the wall reduce this efficiency in my view. Nevertheless, the vents are there anyway so if you use either the Gas Fire or the Central Heating Boiler, the room will be ventilated as usual.

I think the idea here is what can heat the room quicker, and then maintain the heat in the room with little cost?

Because the Central Heating will heat the hot water cylinder also, unless you turn it off in the Hot Press, it is slow to heat the one room. Lots of heat unnecessarily lost in pipes too.

I tend to run the heating on a daily 'timed' setting. If I need a boost in the Living Room in the evening due to cold weather I top-up the heat with the gas fire. Makes it nice and comfy!

what about closing the vents when rads on. Won't cool as fast. Don't do it with gas fire obviously.