strange problem recording hd

[Mixedbag]

Hi, I wonder if anyone has any ideas about this:

I have a Comag sl100hd receiver and can connect an external hard drive to it via usb. I record programmes fine on to the hard drive EXCEPT from BBC HD. When watching the HD recordings after 39 minutes the recording goes back to the start for 8 minutes, then carries on at 47 minutes into the recording i.e. an 8 minute section is missing. I've tried a few solutions, currently I set the timer for multiple 30 minute recordings which kind of works but is pretty unsatisfactory really.

I would love to hear of a solution - even an explanation would be something.

ps I've tried 2 different hard drives and the same thing happens

Cheers