Thanks for your comments. I tried all the usual turnoff/wait/turn on routines but nothing worked and I had nothing for about an hour. What really made me annoyed at the time was the fact it happened about 14:00 when the Superbeam cover ends for the day.
They have no number for emergency support out of office hours which then makes me at least, a little desperate in case I have no TV for a while.
However, again, thanks for the comments to my original post.