I was fully aware the OP was in NSW and my opinion is the same. If you look on the CTTT web site you get this
A lot owner effectively owns the airspace (and anything included in the airspace) inside the boundary walls, floor and ceiling of the lot.
Lot airspace may include balconies and courtyards. Everything within the airspace must be maintained at the owner’s cost.
Generally speaking the bylaws allow the OC to do maintenance of the private areas if the owner fails to maintain the area to an acceptable standard and the owner is then billed for the cost of the maintenance. Allowing owners to ignore their obligations without penalty (or allowing the BC to do it with charge to owner) is a receipe for disaster.
My opinion is that if you took this sort of issue to adjudication the adjudicator would rule that the BC manager or OC cannot spend BC money on private areas without a very good reason and at the very least a majority of the owners voting in favor, as to do otherwise would undermine the Strata concept of having common areas and private areas in one complex.