The OP did not mention if the heating system had TRVs throughout. I have come across systems where all there was a programmer with no room stat and all the temperature control was through the individual TRVs in fact a friend of mine had that exact system. I have virtually the same having equipped all my radiators with Hive smart thermostats except for the bathroom which is the official system bypass and the kickspace heater in the kitchen which has its own thermostat. If the OP has a system as mentioned above the unwired room stat may just be a redundant item from a previous setup.

Richard