Well done - the bike looks very presentable.
Beyond saying that the bike is "Australian made" it's going to be hard to put a name to it. Rob Saward and I are working on the second edition of the A to Z of Australian-made Motorcycles, and the count is currently 530+ different makes, mostly pre 1920. Of these, many used the Fafnir/Chater Lea combination, and quite a few were located in Victoria. Give me the town, and I can add more.
To give a taste, if I flip through the draft of the new edition for Victorian-built bikes with Fafnir engines, I come up with Acme, Alma, Alphington, AOV, Astley, and Austral - and that's just in the As!
Back to your bike. I like 1911 for the date: the 4 1/2 h.p. i.o.e. Fafnir is about right, as is the B&B carb and the open Bosch. The frame is a bit of a hybrid - mostly CL, but I suspect that the steering head lug comes from another manufacturer. The one-piece CL lug of the period was 8" long - fine for CL's own fork but too long for most Druid forks.
The Lycett pan saddle you have fitted is probably a couple of years too late for the bike, but your bum will thank you once you get out and ride!
If you need to give the bike a name (for the tank or rego), "Fafnir" wouldn't be out of place. Quite a few Australian-made bikes just carried the name of the make of the engine: Fafnir, Precision, JAP, Minerva, Peugeot, and so on.
Cheers
Leon