Frozen HDX Screen

The screen on my HDX is frozen and constantly shows the Naim generic disc logo with the words "Waiting for Internet".  Touching the screen does nothing and the remote doesn't help.  I can still control the player as per normal through my MacBook and the IP address or through my iPad app.  Interestingly, if I rip a new CD the internet lookup functions normally and track, album and artwork all download as you would expect.  I have no problems with the internet (posted this didn't i?).

I have tried the obvious approach (rebooted the HDX, and rebooted my wireless router).  Any other ideas gratefully received.

Thanks