Higgovale Quarry and the quarry on De Waal drive both have climbing routes but are seldom climbed at because of the risks of mugging etc. Also the climbing is not very good (blasting and other quarrying techniques fracture the rock and make it likely that large pieces will detach). I know they also have trance parties in the quarry on De Waal drive.
I would not recommend either of these sites as a venue for the heritage center/climbing school/lifestyle center. Although they are probably one of the few climbing areas where you would be able to build anything as most (all?) of the others are in the National Park and the land would have to be deproclaimed by a Cabinet meeting. Which is unlikely to happen unless you run a toll road and need a party venue for your business...