There's nothing different about how any BBC channel is carried through Virgin's network as any other channel, that's why I asked whether it's any one in particular - BBC1-SD? BBC2HD? BBC news HD? CBeebies HD?
Any fault with your TiVo's video output would affect all channels indiscriminately. Can you post a picture of these lines that you describe? I'm wondering if you're describing picture breakup and/or pixellation, which is usually a signal fault.
The more detail you can give about your fault, the more someone is likely to be able to help.
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