Exact location of 'Hell' (main campsite)

This is for the Aussies...

Ok so I'm on a bit of a mission to find this place, and as usual the people who made the film are being elusive (can't blame them).

I've done a fair bit of research by googling and using Google Earth and come up with these main points (that are either a logical assumption or direct quote):

- The scene where they are driving/hiking to the campsite is shot in an entirely different location to where the actual campsite is. It is most likely these parts are shot in Dungong & the Blue Mountains.
- The campsite (not the trails) is quoted as being:
"45min from Sydney"
"In Sydney's Northern Beaches"
"In a nice little park tucked away in a nice little reserve"

Looking on Google Earth there are about 15-20 reserves in Sydney's Northern Beaches and some of them are indeed little. Therefore we can assume it is in a small reserve about 45min north of Sydney in the Northern Beaches area. This narrows it down quite a bit. (On the assumption the director isn't lying lol)

Does anyone have ANY idea where this might be?

Thanks!