One would nee a permit for any premanant structure in our place in WA.

So if we bought a shed from Bunnings, for example, we could put it up no problems, unless we bolted it to a poured concrete slab. We could bolt it to a paved footing with no permit.
It needed to be at least 1.5metres from one fence and 1mtr from the other. Must be under 6metres square and temporary to be built without a permit...

They are all different basically, your best bet will be to call the council directly, tell them exactly what you want to do - position, dimensions, material - and ask them to send the regulations to you in writing.