Thanks for your note.
I am running a BT Hub for broadband through the same line and the Hub is still working (or I would not be able to send this email) so I do not believe it is the actual phone line that is the problem.
Are there any other checks or changes I could make to the Panasonic Main Base or phone handset that would enable me to get this thing to work?
If not, are you saying I have to replace the phone set/main base altogether?
Tested phone by taking it to a neighbour - phone works fine - broadband then stopped working. It is a fault on the line which BT are now working on.