I had the same problem as well. I was trying to record Channel 4 in Her Highness's absence whilst I watched a useless football game. The monster kept switching off, kicked it but this time it didn't work. Had to resort to the TV until the game finished. ( It was by half time ! )
Thankyou for you suggestion but I do not have an Interactive option in Settings. This could be because I still have the original 2005 setup. I did try to up-grade using an old computer but to no avail and, as the box was working well, I just left things be. I have recorded several programmes since, all without a problem. The only other problem at the moment is signal strength. We are just "round the corner" from sight line to Emly Moor. It is undergoing work and has a temporary aerial and will have for some time to come. This seems to affect our evening signal strength, especially on some BBC channels. Can't see that has any bearing on the problem of the other evening. However, thankyou for you suggestion.
If you're using the 2005 firmware, then you really are going to have lots of problems sooner or later, especially when you have to re-scan for channels. It really will be worth trying to borrow a laptop from someone and updating to the Toppy forum's recommended firmware.