You are entitled to see a floor plan because the changes to the layout could affect the amenity of adjacent flats (especially the one below). The floor plan changes will also have to be approved by your local council via a DA. Even if the annexures aren’t required as part of the by-law, they should be provided before the by-law is approved. The Tribunal will only overturn refusal of permission if the grounds are unreasonable. The renovator needs to provide all the information you want or face the prospect of refusal.