Hi Inspired,
Don't bother looking, you just will not get it in Australia!
In Vietnamese it is known as
Mai Vàng, it blooms profusely during
Tết Festival or Lunar New Year. For southern Vietnamese, it is almost sacrilegious...
A few years ago, Mr. Hanh Nguyễn did import about 20 into Victoria -- none make it through alive!
There is a similar plant in Australia --
Ochna serrulata, which in QLD, and NSW are weeds.
One of mine, which is dead now
Ochna serrulata's leaves are much smaller, I would say about 1/6 of the Ochna Integerrima, the flowers are smaller too; and are facing downward instead of upward like Ochna Integerrima.
Have a good weekend
