Smart thermostat won't pair

FireFury

I have just moved into a house with a Tado smart thermostat, extension kit and internet bridge, and basically can't get any of it to work reliably. The app says all of the devices are connected, the current temperature is 15 degrees and it is set to heat to 19 degrees. The app says it is heating, but the boiler is not actually being told to heat by the extension kit. The smart thermostat said "off" and none of its controls seemed to be able to change that. So, I factory reset the thermostat and tried to re-pair it with the bridge. The bridge is in pairing mode, but the thermostat eventually give up and displays "EO".

At this point I'm about ready to throw the lot in the bin and install a different system.

Can anyone give any advice on getting it all up and running?

Thanks