If you don't wish to situate your phone DECT base station at or near the Hub you can use this:
https://www.bt.com/help/user-guides/phones/digital-voice/digital-voice-adapterI managed to get one free from BT via my sons BT account, he had upgraded to FTTP with LL but not taken any of the free options, I had already taken the free digital phone option with my FTTP contract, only get one or the other for free.
If you have not taken up any of the digital voice packaged options when signing up for your FTTP then you can still get a free adapter, my sons FTTP install was over a year ago and the free adapter order still went through.
I noticed later in the day, though the dial tone was still on the copper line
My FTTP install with digital voice is close to 3 months in place now and I still have a dial tone on my old UG copper line, 17070 gives a "circuit ID" of a number on my exchange (not my original LL number) but "ring back" doesn't work nor can I dial out or receive calls on that number completely to expectation.
My digital voice works perfectly (on my original LL number) using the BT digital voice adapter and existing Gigaset DECT phone trio so nothing to worry about, likely would never have been aware of the copper line still being alive except for an old hard wired analogue handset still connected in a spare bed room.