Hi Lanxer,
Thanks for posting and welcome to our community 🙂
If you have your phoneline through cooper wire any individual handsets would need their own socket, this would need a technician visit and would be £99.
If you have the phoneline through the back of the hub, this would also require a technician of the same cot to add a special extension, your best option however would be to use wireless/ radio handsets, so only the main one needs to be connected to the hub/ socket and any additional handsets just need standard power connections.
Let me know which you have and if you would like to arrange a technician visit.
Alex_Rm