We’ve seen lots of pretty plumeria before, mostly in San Diego, but in Australia, they seem to be Australian Big—very few have blossoms that we could reach, even if we were crass enough to pluck them from someone else's plant.
This one (close-up above, perspective below) is at the Perth Mint.
The Royal Botanical Gardens in Sydney had a number of large trees, as well as a lot of small plantings, some still supported by stakes.
This tree was on the Low Isles, in the Great Barrier Reef. It was about 30’ tall, and had rough bark at the base, unlike the glossier bark on smaller plants.