welcome to Stainless-Steel-Rails .co.uk
700mm High 1800mm Length T11 Style 2000 type Single Panel Radiator With Convector

Only choose a double panel radiator if the wall space available is really small, if there still isn't enough room then it is possible to get a fanned convector radiator. These have a fan unit that blows warm air out, a small version of this is designed to fit in the kick space of kitchen units.
Radiators do not burn gas, therefore turning radiators off will not save money. In fact it will probably put your fuel cost up as this creates cold drafts in the house because cold air is heavy and hot air is light.