jliv – quite frankly I think that you’re being a pit precious. One of the reasons that you rented your Unit in the building was probably because it had security, and now that the new Managers are doing what the Owners Corporation wants by ensuring that only residents and bona fide visitors have access, you’re dissatisfied.
All of that said, provided you approach them reasonably the Managers and their Staff have no right to be discourteous in their dealings with you, and as they’re employed by the Owners Corporation of which your Landlord is a member, any complaints that you have should be raised with your Landlord via their Property (Rental) Manager.
Quiet enjoyment is not relevant, and you have no other grounds to seek redress via the NSW Civil & Administrative Tribunal in my opinion, but if you really don’t like the environment in what sounds to me like a well run Building (at least from the perspective of protecting the safety of its residents), then have a chat with Tenants NSW who may have a different opinion; although I doubt it.