I finally succumbed and signed up for the free prime offer during prime days last week and ordered a few things I had been eyeing… They arrived today. Ordered late PM on Wednesday, and got the dispatch notice this morning, then shortly after, another email saying delivery would be today. I thought it was a system glitch - but no, sure enough, arrived a couple of hours later.
Amazon just got bumped up my list of preferred vendors. Happy chappy.
Amazon has been doing Sunday deliveries for years. It's not new. They use their own logistics processes both in-house (Flex) as well as third party like Dragonfly so not always reliant on AusPost.