My next question is, I have installed smart radiator valves (also Tado). Is there a way to only switch one of them on without the need for the wired thermostat to be on (entrance area with radiator without valve that can be opened or closed)
In the main radiators are in parallel with a by-pass valve so each radiator can be controlled individually, and as hot water returns to the boiler it will auto turn boiler first down, then it will cycle off/on once at minimum output, the wall thermostat is only required so on warm days the boiler will not cycle on/off all day, as without pumping the water around it does not know if any TRV has opened or not. But to set the TRV, lock shield and wall thermostat to work in harmony is not easy, so the idea of a hub which collects info off each TRV and tells boiler what to do is far easier to set up.
Most wall thermostats explain how they work, but Tado is rather poor at telling you how it works, with Hive it tells you exactly how it works, Nest does not any longer work with TRV heads, Honeywell EvoHome has the wall thermostat control I think 6 TRV heads, and Drayton Wiser the TRV head tells the wall thermostat when to fire the boiler, some like EPL work only with motorised valves.
Main difference between a motorised valve and a TRV is the motorised valves are hard wired and have micro switches inside them, they both do the same job, personally I want to have the ability to select each room, rather than a group of rooms so use TRV with electronic heads in main house, but in the flat under house use a motorised valve so whole flat can be turned off on a single control.
With a thermostat in the hall it also needs a TRV, as when you open the door to outside the hall will cool rapid, and so it needs to reheat rapid, but before it reaches the temperature to switch off the wall thermostat the TRV needs to throttle back or it will switch off boiler before rest of house is warm. It can be done, I did it with mothers house, with non smart stuff, but with smart stuff it depends how it can be set.
When I tried with Nest and Energenie I found it auto set both at same temperature (until google withdrew support) but since the TRV in lower than the wall thermostat and closer to front door, it needs setting around 2°C cooler to the wall thermostat, and this was not available, so my TRV and Wall thermostat have the same times when program changes temperature but different temperatures set.
It seems in USA they have released satellite Nest thermostats which tell the main thermostat to keep boiler running if room with satellite in is still cold, but not released here yet.
But at least one can read how Nest works, Tado is so hard to read instructions I rejected it.