Thank you Maris.
I never thought of a polarising filter as I waited and waited for the right light to get the reflections. The aim of the photograph was to somehow depict the highlights without them blowing out.
Freshly expanded leaves are the glossiest and have the best reflections, so pretty much every leaf you see here is quite young and a lighter shade of green than older leaves that are out of the frame. The central leaf, which is uncurling and expanding, is the lightest coloured green and this difference is only there whilst it is unfurling.
I needed full sunlight and at this time of the year, early to mid October, full sunlight only happens between 07:30 to around 08:30 on cloudless days.
Living in Melbourne meant I had a long wait.