Just pre-war or just post-war is often a difficult call. There's a "1914" single cylinder, shaft drive FN current for sale here in South Australia - it's a lovely bike but I strongly suspect it's actually 1920-build. For FN the war was pretty clear cut: Liege was overrun, the FN factory was taken over for German war work and there were no motorcycles made from 1914 until 1920. The first bikes of 1920 were pretty-much 1914 models.
Not sure what happened at Excelsior, but they did manage to build 5000+ Welbikes during the war. The Excelsior/Waratah in question has some pre-war-ish features, like the gear change and the bolt-on rear subframe, but a hint of postwar with the headlamp and (maybe) the front fork. The other well-known Australian bike of the era was the Acme (much more Australian-made than the Waratah), and it used the Sackville pressed-steel fork pre-war and the Webb post-war, so maybe there is an element of that here. Some Acmes for the early war years (1940-ish) used the "modern" "bullet" Villiers headlamp rather than the old "tobacco tin".
So very hard indeed to spot differences between a 1939 model bike and the first bikes delivered in 1946, when getting stuff out the door was more important than adhering to a catalogue specification. The 1946 Waratahs and the 1946 Excelsiors may have differed: if there were left-over pre-war parts in the factory I know where I'd send them! Numbers will give more clues.
Leon
