Ascend C. What wonderful history for you. I wonder if your mother got a selfie with Smithy with a Box Brownie of those days? If you have time read the book "Outback Airman" by Harry Purvis with Joan Priest published in 1979 and probably held in most libraries and certainly available on the internet. In it there are many stories of Smithy and Harry Purvis flying together. Maybe Neutral Bay joy rides are mentioned.
His story in the book of how he took the surrender of 10,000 fully equipped Japanese troops in Bali at the end of the war is both serious and amusing. Knowing the Japanese General nor his aide nor any of the officers had any English, Harry signed the surrender document as "Franklin Delano Roosevelt." In fact Harry Truman was then President.. Roosevelt had died a few months earlier
I corresponded with Harry Purvis for many years until his death due cancer in Cairns in 1980.
See:
https://www.abebooks.com/book-search.../harry-purvis/