I mentioned above that the bike itself may not be Dalm. Having a quick look, I'm fairly certain that your "Dalm" was assembled in Adelaide. "The Mail" for 10 Jun 1916 has an article:
"Dalm Two-stroke.
A consignment of Dalm two-stroke engines have been landed and unpacked by the South Australian wholesale agents, Messrs. J. N. Taylor &. Co., Limited. These are being built into two-stroke mounts locally, and the completed article looks neat and attractive..."
J.N. Taylor were wholesalers, but I believe they did assemble bikes as well as import them. (I have a c1921 8 h.p. Victor Blackburne which I believe was assembled by JNT using Blackburne motor, Burman gearbox and R. Walker & Son (Excelsior) frame set.) It seems that the Dalm motorcycles were sold by the Wyatt Motoria in Adelaide as the "Wyatt Dalm" - Wyatt could have assembled them, but my guess is they simply sold the bikes Taylors assembled. At least some used a two speed gearbox, and judging from the advertising most seem to have been built pre 1919. Not sure about the origin of the frame set; I'm not familiar with the lugs but they may also be from a UK source, perhaps RW&S.
So, subject to confirmation and more research, I'd say you have a c1916-17 "Wyatt Dalm" motorcycle, assembled in South Australia. Nice.
Leon