Tado v2 pairing question

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Hi I hope somebody could help me regarding the installation of th v2 extension box.
I purchased a used v2 tado of eBay the package came with a thermostat, bridge and extension box.
The seller hasn't removed the devices of his house at the moment but he said he will do.
My question was does the sysyem need an internet connection in order for it to work, as I've installed only the extension box with the boiler but it won't switch on the boiler via the thermostat or by pressing the button ontop of the extension box i used the switched live 2 diagram to wire it to the boiler.
In order for me switch on the heating I have to remove the extension and install the link cable back into the boiler.
Does this system not turn on if a bridge is not used for the time being or will I have to wait till seller removes his house so I could register it on my house for it to work.
Thanks