Hi Dani
I’ve never dealt with something like this but this is the process I would follow:
Easiest – sell the property prior to notifications being sent for the future works.
If not possible I would then look at Section 710 2(e) to serve your notifications:
(e) by fixing the notice on any conspicuous part of the land, building or premises owned or occupied by the person.
That’s if you can actually gain access to the property. I have seen many examples of where a Council has posted notifications on the front fence of a vacant property in a plastic sleeve to give notice.
Unfortunately, I am not so familiar with the Environmental Planning and Assessment Act 1979 which may overide the above.
In the end it might require a legal opinion.