Worcester Boiler - Wired Extension not working


I've installed the wired extension kit and everything appears to be working on the app but it doesn't actually turn the boiler or hot water on/off. I've got a Worcester Greenstar 28i Junior boiler and a wireless thermostat at the moment.

I've followed the instructions to connect the +/- outlets in the extension kit to the B/B connection in the boiler but nothing happens - some other comments suggest that there is a setting to change in the extension?

Tado customer service has been poor for me - the only response I've had all week is a request for photos, then nothing when I sent them!