@Blackknight I checked the outage page for Box Hill and Optus are aware of it.
https://www.nbnco.com.au/support/network-status I checked in Box Hil South and the NBN site is reporting "Planned maintenance is currently taking place".
xxx CANTERBURY RD BOX HILL SOUTH VIC 3128 Australia
We are currently performing planned network maintenance. It started on 27 Jul 8:30am and will finish at 27 Jul 6:00pm. Services are expected to be affected for a total of 3 hours during this time.