Going by the staging I think (almost 100% sure) Skyhooks were opening for Sherbet that night, so I am thinking the concert must have been in Sydney during the Slipstrrem tour. Nice to hear the original arrangements of some soon-to-be all time classics too. As for the promo, at that time they often recorded B & W and Colour clips at the same time, for other shows, this could be what happened here.

I wondered about the slipstream sign. Being the opening act explains why the audience was so quiet - they were waiting for Daryl & the boys. At this stage I don't think Skyhooks were well known to the casual pop fan

It being pre-Countdown I would say either act would be well known outside of their home states, despite Sherbet being a hit act since around 1972, (it takes a while for a fanbase to become established in any other town in those days).

I LOVED this show, it was so camp and fabulously over the top for it's time.

DId anyone else have the big lines across the screen in sections?

I did notice that, could be the same sort of interference the cameras had in those days as two other clips I have seen have similar traits, one from Billy Thorpe and the '72 Aztecs and the other is Zoot's "Eleanor Rigby".