Response to Watchman’s comment 14: If there are no children on the premises then the child lock can disengaged and the window opened in a normal manner. However, the locks must be engaged and the opening restricted to the legal limit whenever children are on the premises.
Response to Watchman’s comment 15: You are obliged to grant access to the Owner’s corporation for the installation of the child locks and for all of the necessary safety checks. These checks are for your benefit and for the safety of all other people in your building.
However, checks by real estate agents are a totally separate matter. If you have an issue with the number of checks by your real estate agent then this is a matter you would need to take up with them, or through the Office of Fair Trading mediation process etc.