Are the TRVs (thermostatic radiator valves) on your radiators adjusted about correctly?
It is best to calibrate them accurately, but here’s a quick fix, assuming living room is at 21C and elsewhere at 18C.
The room thermostat is best placed in the main living area, most of the time. All TRVs in the same area should be on maximum, so they don’t conflict with the room thermostat.
TRVs outside main living area, in homes up to three bedroom homes set at 2. Four or more bedroom homes should normally have zoned areas that allow separately timed heating of bedrooms.
Unused bedrooms set at frost setting and close the door.
The room thermostat may be fixed to the wall in the hall. If so the living room TRV should be at 2.5 If you are the hardy type, reduce all values by half a point on the dial. Your living area should then be around 18C and elsewhere 15C.