Great show, Savile as always showing that whatever else he was, he was a great presenter, made it all look so easy. Shame about the video quality but as Doc says, better than nothing. Lets hope the other editions turn up soon.
The 07/05/81 (Peter Powell) clip has audible voice links. It's a pity the BBC couldn't go to 4Shared, download the clip and then just dub Peter Powell's voice over their recording. It must be too much trouble for them
I've asked around and can confirm that the BBC has a copy of 7/5/81 where Powell's audio cuts off just after the Stray Cats. He says "Hit 26...." and then blissful silence from there on. Until the charts that is where over CCS he counts down from 30 to 21, and REO Speedwagon get an intro. Then silence while he's in-vision but he comes back again to count down from 20 to 11. Silence again. The Nolans get plenty of "audience noise" but curiously their applause at the end is quickly faded out. In-vision silence again, but the top-ten is voiced. I'm guessing the count down sequences were pre-recorded.
This is a copy of a PasB (programme as broadcast - essentially an off-air recording), and would be the most easily accessible to programme planners, schedulers etc., for viewing.
There is recording however which isn't a PasB dub, but I've no idea what the audio does on that.
I suspect whoever views the programmes prior to planning the schedule has just watched the easiest one to view, and made the decision from that. Clearly a copy does exist with audio as Neil Barker's brilliant page shows - and they're pretty good quality so I don't think they've just come from some old home VHS recording.