A small proportion of my recent recordings (Sky via Scart, IR blaster) have had the channel change not kick in for about 30 seconds, rather than the usual 1 second or so. It's the signal not being sent to the digibox, rather than a slow change by the box. Today one show had a four minute delay before the change. Nobody has been present for these recordings, so it's not someone noticing a missed change and correcting it. Any ideas?