Hi Dean, can you ensure that the inbound call route from the line port is definitely set to {ph}?
From what you've said, the OBi is getting the caller ID and it's getting lost between the Line port and the Phone port - the only thing I can deduce as causing that is the inbound call route.
First, go to OBi Expert and change LINE port -> InboundCallRoute to say {ph} - wait for the OBi to reboot and do a quick test to see if it passes caller ID.
If this doesn't work, go to the device local UI via it's IP address and go to the same location locally and change again the InboundCallRoute to {ph}
Let me know how this goes. Next step after this would be to factory reset and see if caller ID works out of the box with no changes.
- Mark.