A few more snippets from Osprey CA-110 on the Dutch and RAAF use of Do24 in Mar/Apr 1942.
Looking at a map, Medan in near the northern tip of Sumatra. Looks a lot closer to Ceylon/Sri Lanka than to Darwin or Port Moresby. It may have been more likely a high wing Dutch PBY evacuated to Ceylon, rather than an Australian based Do24. There's no mention of the name Medan in reference to the Do24 flights in the Osprey volume or in the "Dutch Naval Air Forces....." book with respect to Do24 or PBY evacuation operations.
No worries of being out of touch, Brian. I expect you've been busy preparing more books that I'll want to buy in future.
...geoff