Connecting your old phone extensions to BT's Digital Voice system

In the UK we're being switched over to the Digital Voice system which means the old landlines are disappearing and will now only work via the internet. This involves physically disconnecting the phone signal from the exchange. From hereon, your landline can only operate from the WiFi hub. This should have a phone socket on the back. However, the installation comes with no help to connect your old extensions - many people suddenly discover their bedroom or kitchen phone no longer works. And you'll get no help from BT or the BT Openreach engineer either who comes round to set up Digital Voice. This video shows how simple it is to reconnect them by using the old wire but connecting that to a cable which goes into a doubler on the back of the WiFi hub. Hope this helps! Incidentally, I have no mobile signal in my house which also necessitated this solution.