@ericmark is spot on. The thermostat should be in the last room to warm up, the other rooms then don't overheat because their TRV's shut them down before they do. If you don't have TRV's fitted to the radiators in all of the other rooms except the hallway, fitting them would be the solution. So I recon your room thermostat is currently in the best place.
As the room thermostat is measuring the temperature of the room in which it is located, you could move it to one of the warmer areas, so that the heating is turned off earlier, but that would mean that the hallway would go off as well, meaning it would be even colder than it is now. However relocating a thermostat is tricky, here are some tips:
Tips for Room Thermostat Location:
The room thermostat should be in a room that is not effected by other sources of heat such as an open fire, cooking equipment, or direct sunlight etc. It should not be somewhere drafty or too close to a window, especially if it's one that is opened in the winter.
Secondly it should be in a cool room, ideally the last room in the house to warm up. That way, the other rooms will be warm enough, (but not overheated because of their TRV’s) before the room thermostat switches the entire heating system off. To achieve this, it may involve downsizing the radiator in the actual room where the thermostat is located.
The radiator in the room with the thermostat installed should
not have a TRV fitted. Otherwise the TRV can interfere with the correct operation of the room thermostat.
The thermostat should be mounted about 1.5 metres from the floor, and not close to, or above a radiator.
Preferably it should not be on an outside wall, (although if you have well insulated walls, this is not quite so crucial.)
It should be in an area where air can circulate easily, not in a corner, or hidden behind curtains, or furniture.