I'd try what Ginge done mate, switch off at mains, press and hold the backup button on the box, switch power back on. Keep finger on backup though, and after a few seconds, all the lights on the front of the box will light up. Take your finger off the button.

Leave it like that, should take about 10 mins then all the lights will disappear, and go back to standby. Leave it like that for 60 seconds then try turning it back on.

That's really all I can think of chap, if that don't fix it, I'd say it's kapoot!