In my BT Account I have Calling Line Indicator ON.
I have for a few years had two phones on my in-house wiring.
A BT Paragon 510 Phone and a BT Decor 2600 (Call Blocking Phone) and both phones displayed the Calling Line Numbers.
However, since going Full Fibre my BT Paragon 510 Phone no longer displays the Calling Line Number.
The BT Decor 2600 (Call Blocking Phone) does still show the Calling Line Numbers.
The BT Paragon 510 Phone is actually connected closer to the BT Hub.
Is there some reason for this or is there something I can do t solve it?
Seems for some phones caller display just doesn't work with BTDV. Even BT ones. I'm having the same issue with BT3530. You'll need to request or buy a BTDV-compatible phone from BT.