There are two trees fairly close together in a golf course floodplain. First four photos are one tree The last two are the other. Characters match native sycamore more than London plane, but there are some ambiguities. Leaf lobe width, pale grey-white colour of inner bark, rough outer bark on bigger tree match native. Most seed heads are single, but some are paired (as in photo). The trees seem to show on old air photos dating back to 1950 before the golf course or the surrounding suburbs existed. It would be good to resolve this because the trees have been used as a seed source for native plant nurseries. @wdvanhem, @michael_oldham, @samuelbrinker, @brian_ford, @wjcrins, @steveinat1... are you able to offer your expert opinions?