It has been about 60 years since I saw that film so I can't remember if the climber is on the actual arete or a bit in from it. Pitch 2 of Black Rose (20ish) climbs about 4m in from the arete. Lucas Trihey who was very involved with the production of the film happened to put up a route called "The Edge" which climbs the arete on trad at 19... I suspect the footage might have been filmed on both these different pitches. It's the gr 27 pitch below these where the whipper pics have been taken.
Just to explain why it's not in the latest guidebook. The area is covered in the previous ed of the guidebook. When we were working on the latest edition I figured not much had changed at Hanging Rock and the info was available for anyone who was keen. The area had just had a fire through there and also the parks had put a gate across the road suddenly making the area a whole lot less accessible... Anyway these factors just helped with the decision that it was more important to put the effort into covering areas that hadn't been in any guidebook for years. We'll probably add it back into the next edition.
Speccy place, good for photos, but you have to rap 50m just to get to the top of the routes. A lot of dicking around for a little bit of OK climbing...