OK last attempt at this one. I had to cut out docklands all the bridges, as much of the roads and streets as possible, and then chop shorter sections out of the city as well.

 

The problem with Melbourne is that the CBD is much larger and taller than most other states so is much harder to get working properly.

 

The size of this one is roughly the same as the others and is actually smaller than most of the shopping centres I have done so if you can't run it then I have no idea.

 

I'm done with cities now so if anyone wants to do more work on it like lights, message me and I can send you the blender file.