Was just browsing the Intelligent Homes website and noticed their Sonos Arc, Sub and Surrounds kit was marked well below Sonos' RRP of $3176 meaning you save 18% ($577.00). Sonos' product listing and price available here https://www.sonos.com/en-au/shop/surround-set-arc-sub-one-sl
These guys are located in Perth and their website mentions pickup from their location. Unfortunately they're closed weekends so I cannot call to confirm if they offer delivery or not.
https://www.ozbargain.com.au/node/674321
This is a better deal