Separate thermostat with smart TRVs

Hi all,

I have smart TRVs on most radiators which are working well. However, the location of the thermostats behind curtains, next to radiators and low to the ground affect the temperature reading. There thermostat quickly senses heat from the radiator and thinks that the room is hotter than it really is. Whilst this can be sorted with the 'offset' function we also have a log burner in our living room which heats the room up way beyond the temperature that the thermostat picks up.

I was hoping to add a separate thermostat in the affected rooms to get a more accurate temperature reading.

I know there is a new wireless thermostat but I was originally planning on buying a second hand wired thermostat and using wirelessly, as it seems to function perfectly without wires.

If appreciate any advice before I splash out on more kit. Thanks for your help.