how to relate temp in room with radiator without TRV

[tiggypoo]

Idiot question coming, sorry
I live in a flat with thermostat in hall. Tiny bedroom 2 has a large radiator with no TRV. This room gets too hot when heating on , much more than rest of flat. I understand that radiators without TRV is a mandatory thing, but how can you regulate temp on that room?
If I turn the thermostat down, the rest of the flat is then too cold.Thanks for advice.

 

[TCCHeating]

Is there a radiator in the hall? You are right one radiator must be left with no trv. This should be the radiator in the same area as the room thermostat. If there is no radiator in the hall, you should look at relocating the room stat to a more suitable location. (Or you could get a small radiator installed in the hall, this would then be the 'always open' radiator. You could then put a trv on the bedroom radiator