I was just about to post this problem for help but it appears to be fixed now . However, I thought I'd post it with the workaround in case it helps someone else, or highlights an issue with the router/firmware/phone compatibility.
Switched a few days ago from BT broadband/digital voice. Broadband is fine, phone calls fine. Only problem is the caller ID isn't working. The first call after the line was connected showed the ID, but every call after that just says 'Incoming Call'.
I rebooted the router and again the first call showed the ID but after that every call just says 'Incoming Call'. The caller ID is listed in the call log on the phone after the call though. This is on a BT4500 handset btw (two handsets, base station plugged into router, second handset connected to first wirelessly).
FIX: Switching the phone from the TEL 1 socket on the router to the TEL 2 socket appears to have fixed it. 🤞
