The room stat will call for heat if the temperature drops but of the rad stats are set at too low a setting then they won't allow the hot water through.
If you're going with a smart room stat and dumb rad stats then open the rad stats to 5 or 6.
Thats a really good question and I would like to know the answer too. I think that Tado would suggest that you get a smart rad thermostat in the living room as well. Otherwise yes, you could get conflicts I guess.