Kenuppa – are you in Queensland? If so I am not in a position to answer that question. It is my understanding amendments were made to the Building Act in that jurisdiction to allow for installation of solar panels – the Committee can impose conditions.
Have a look here.
In NSW you would be granting exclusive use of the relevant area so that the panel could be installed, usually you would look at a by-law that includes provisions relating to the owner taking responsibility.
In that case there is no time limit (unless the by-law says that there is), an exclusive use by-law runs with the property.