I know this is bumping a thread that is 9 years old but I have been going through a batch of Beta videos from the mid 80's with footy recordings but it has a lot of other segments of material as well.
Some of them have a bit of music recorded from Countdown, Sounds, John Torv's Music Video, Hey Hey etc. although generally nothing to get excited about.
I did however find at the end of one tape a segment from Tonight With Bert Newton (Ch9 1984) where Bert was discussing music with Molly (not sure what Molly was doing on Ch9) and he introduced a Sherbet live performance in the studio as the last ever Sherbet performance as they were breaking up after this TV gig. Ironically they performed a song called Tonight Will Last Forever.