I built something similar, and it supports the ASCOM Switch capability.
With some modification, you could make this fit for your purpose.
https://www.youtube.com/watch?v=SEDUN2QxzrE
NOTE: I don't love the board I used because it requires 12V on the switching side (which is just annoying) - If you could find one that could work straight up off 5V so you could switch it from the Arduino, that would be better.
Check the description on the video for links to various software you can use. It's all pretty generic stuff.
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As for powering 240v programatically, I used to have one of the older Digital Loggers power strips (they do not have australian plugs, but can run off 240V). They are expensive for what they do.
There are a number of WiFi controllable power boards you can get that use ESP chips and can be flashed so they can operate locally (rather than using cloud providers). They typically use SONOFF or TUYA firmware. I have a backburner project (so many of these backburner projects!!!) that I was going to use ARLEC GRIDCONNECT powerboards (or single plugs) and flash them. Instructions on this here:
https://drive.google.com/file/d/1sUa...koWnsWB-7/view
I have a bunch of home automation gear that allows me to interface with this stuff easily, but that's an entire rabbithole to go down.