As Stephanie said, the Medicare you get here as a UK citizen will pay for everything in a public hospital. If you were to go private or want a private room in a public hospital etc then you'll have to pay for that. I don't think the private health insurance you can get on that visa would be worse it or cover anything more but you can always check. Though they are very expensive from memory. I just had a similar conversation with another mum from the UK a few days ago so I thought I would also mention in case you were thinking of using daycare here: Prices are between $150/200 a day, and if you aren't PR or citizen, you do not get any rebate so you have to pay full price.
You should research if you get access to public healthcare with your visa type. For private health cover, you need to have 12 months waiting period before you can get pregnancy coverage (i.e. need to have private health insurance for 12 months and only after that pregnancy will be covered).
I was on a bridging visa when I gave birth. Went though the public system with no issues. I was still waiting for my interim Medicare card to be processed. I called them on the way to the hospital when I was being induced and they gave me the temp number over the phone. The clerk at the hospital said it wasn’t needed though as I’m a British citizen. I paid for my OB appointments, blood tests and scans out of pocket. From memory it totalled to just under $2k. I was on a student visa previously though which has no Medicare allowed and my private health only covered half of the extras I needed. It’s pretty standard to have some out of pocket but if you’re on a skills visa I believe your blood tests and any extra scans will be covered.
You should consider your daycare plans. Daycare here is wildly expensive especially if you don’t qualify for a subsidy.
Hi I had both my babies under a 482 visa and went through the public hospital and it didn’t cost anything, as anyone with reciprocal health care which the UK has with Australia will be covered. The only thing I paid for was my 12 and 20 week scan. I had a fantastic experience and couldn’t fault my care.