The trunk: The whole tree: New leaves: Established leaves, opposite and elliptic: Definitely deciduous: The seed pod:

That seems to be the response from my queries too. Castenospermum australe, although the pod looks a little small compared to the ones I've seen before. Open up that pod and you should get your answer.I think the tree is a Black Bean, Castenospermum australe, the sole species of a rainforest tree native to NSW, QLD and New Caledonia. I dont know how it would perform as a bonsai.
There's no doubt about it, the flowers are quite distinctive! The leaves certainly look like the black bean....Although in 5 years I’ve never seen those flowers on the tree.