If I install a Tado Horizontal Radiator Therermostat on each radiator will this control each room temperature via an extension kit without fitting a smart thermostat.
Can I link twin radiators in the same room
The Extension Kit is an add-on to the thermostat. You may or may not use it in your setup, but if you want your tado system to control the boiler, you need a Smart Thermostat for that.
Then yes, the Smart Radiator Thermostats would be the ones controlling the different rooms.
All devices in the same room are advised to be configured as part of the same room in our app setup, if you have more than one radiator, all those would be configured and controlled as just one zone.
Many thanks for the reply, can i check that the Thermostatic Radiator valves can demand the boiler to operate when each temperature is reached. for example if all rooms are above temperature and one room drops below that the Thermostatic Radiator Valves in that room would command the boiler to operate until that room reaches temperature.