I needed to reboot my tivo last night when it decided it would ignore the remote completely because of what I'm guessing is a firmware bug. At the time it was recording 3 things and I pressed the channel up button, it prompted with the msg asking for confirmation to carry on recording the current programme or to cancel it and change channel. I selected to continue recording. After this it stopped responding to the remote. I waited until the recording programmess finished and rebooted, remote now working perfectly again so the problem is definitely with the tivo firmware and not the remote.
Only had this happen once, so just a FYI incase anyone from virginmedia is monitoring for potential firmware issues.