I hate technology sometimes :) It's back working again.
I just switched it back on to an HD channel and low and behold its back working normally. No interference or anything. I tried turning it on and off. Switching youview on and off (and it made me retune when I turned it back on). Checked the firmware etc. Nothing made a difference. It's surprised me that its back working.
Very strange.
I had made a video earlier of what it sounded like. Here is it;
[youtube]https://www.youtube.com/watch?v=hHp1xKMZ-2M[/youtube]