The thermostat and T/H device only report to the Zigbee network intermittently and asynchronously. I doubt it would work very well and think you’d want to keep sensing and controlling on the same device, however an automatic calibration function would be more useful. The error between the radiator temperature and the real T/H temperature isn’t constant so it’s be good if the TRV was able to vary its offset by itself. Haven’t to set a constant offset is a bit daft when there is a real value to check against.