I am trying to identify this flower. It was spotted in an Australian Botanic Gardens. I have been advised that the plant was approx 1.8m high and the flowers approx 2cm wide. Any help greatly appreciated.
That's an Apocynaceae, from the species Strophanthus speciosus. Its common name here in Australia is corkscrew flower or poison rope.
It's not native to Australia, though: it's native to Africa.
You can easily identify it by the flower:
Flowers of Strophanthus speciosus in the Royal Botanic Gardens Victoria, Melbourne (source of the image)