Added New Radiator Thermostatic Valves

So, bought 3 new tado Smart Thermostatic heads to complete my system. My system is a Wireless V3+.....works okay.
Installed the new valves in various places, 1 in the Kitchen is giving me grief. Not sure if I understand the tado synopsis which is the reason for this post.....tado documentation is woeful.
The valve installs and initiates okay. The tile called Kitchen appears and I bump the selector from 20 to 25 to trigger the boiler....the Wireless Receiver does not do anything. Well, not always, it sometimes displays the flashing Error LED and the Heating call light, but the boiler remains silent. I've swapped over known good valves but the issue remains the same.
Could do with some help.