You can make the phone connections to the ethernet cabling via leads and adapters leaving your ethernet wiring/sockets intact.
The RJ11 connector out of the back of the hub uses the centre two pins (no.'s 3 and 4) for the line pair and the convention for patching over ethernet cable is that pins 4 and 5 are used.
At the location where you connect the phone, you use a RJ45 plug to BT socket adapter. Ones marked PBX/Master have a ringing capacitor, ones marked Secondary do not.
Always a bit of a fiddle getting the right leads with the right pins connected all the way through (as the manufacturer and supplier info is usually poor). Often you can get what looks like the right lead but the internal wiring is wrong but there is good info on this page
https://www.britishtelephones.com/rj45.htm
Doing this means you can leave your ethernet cabling and sockets intact and just patch in the phones as required. If you ever feel the urge to run in more cable for a better solution, run in ethernet rather than phone cable and give yourself the dual option of patching data or voice.