Seems like I am having the same problem as you.
To date numerous phone calls to bt, reboots, updates, factory resets etc. To no avail
2 house calls by engineers a total of about 6 hours and a 2 hour session on live chat last night which ended by being told the ethernet cable was faulty because there is a red light by the spdif socket?. I doubt it is the cable as I have tried 2 and tried through a power line as well so that's 3 sets of Ethernet cables faulty?.
Thanks for posting. Can you please drop me over an email with your details and I'll look into this for you.
It's unlikely you've had several faulty cables so can you please also send me over your details using the contact link in my profile.