Generally I would say for the location of a room stat you are looking at considering how the house is heated and which areas you need warm.
The room stat will cut off the supply from the programmer to the valve (or the pump / boiler if no valve) so heatign will stop on the whole system.
If the stat is located close to an external door then it will be colder than the rest of the house so the heating would be on longer and overheating the rest of the house.
If you have the stat in an already warm room, say (despite the environment) in the kitchen, then the heating will switch off before the rest of the house is warm.
If you chose a frequently used room (say a living room) then the stat would keep that room to the temperature required and, depending on how the house is arranged, might have say the bedrooms a bit cool (which is good), but the kitchen hot.
Overall I would aim for a location that gets midway warm compared to the rest of the house and then it will average the heating for the other areas.
For the operation you describe, Kingeri, then the living room would be the best place, the only other radiator heating you have is in your sons room for one hour, so the stat would be controlling the heat in the living room, if the wood burner is on the n the heating will go off, but the wood burner should also warm the house overall to some extent. for the one hour you could switch up the stat to heat the bedroom if required, the TRV on the living room rad would switch that off if not required. But as you say seems a bit OTT having a stat.
