There's some confusion with dates here...

The Warwick Farm Autopics photo shows Geoghegan in the Lotus 39 chasing Bartlett in the HMV Trophy race on July 13, 1969. But it seems to me that Geoghegan has now rear wing in that photo whereas the car behind Bartlett's in your pic does have a rear wing.

Unless you can enlarge it and get more detail, I'd suggest it's Stewart chasing Bartlett in the Hordern Trophy of that year or the Tasman Cup race of 1970, most likely the latter.

The Peter Brock A30, by the way, had passed on to Ross Bond by the time the Barry Sharp pic was taken. And the pic of Max Stewart's car in the pits shows Glenn Abbey at the back of the truck with Alec Mildren partially obscured, and it might even be Stuart Randall, not Max himself, at the back wheel.

I am trying to remember who the woman in the checkered slacks is but it's eluding me. The Alto Ford Escort is Bob Holden's.