Also note the different Villiers headlights. Flat back prewar, bullet shape postwar. Tracking the various Villiers headlights over the decades is yet another world of mystery.
So if there was a period photo of an Acme with the pre-war muffler, toolbox and fork but a bullet headlamp?
My Wolf photos are said to be from the 1937 catalogue, from
http://www.historywebsite.co.uk/Museum/Transport/Motorcycles/Wearwell2.htm . One of my favourite websites.
So Bennett and Wood looks OK: Wasp and Hornet from March 1937 through 1938 as rebadged Wolfs, followed by Acme from March 1939 "built" by Bennett and Wood. I don't mind too much "couldn't compete with the BSA Bantam" as a reason to cease production in 1949, but the end of the 9D the same years is also worthy of note.
Utility is not bad, if a bit confusing. Are there surviving photos or perhaps a catalogue? I don't have any real evidence supporting the "rebadged Montgomery" story, but it's certainly plausible.
Cottman Colt is probably ok, as rebadged Model A Royal Enfield, but I can see anything prior to 1939, which is the year RE went to a vertical engine and single-down-tube frame. A surviving CC has the 1939 RE frame, a 1939 RE engine number, but (confusingly) an earlier cylinder with the central exhaust, as used with the twin-down-tube frames. The CC brochure shows the 1939-on RE layout with the exhaust on the RHS. The surviving CC had strange all-encompassing engine plates - not sure if these were an RE feature, but they don't look right.
Waratah is ok.
Simplex was Turner Bros effort c1936 - they were in all sizes 125, 148, 196, 250 - and were imported, but without an illustration I can't say more. Interestingly Turner Bros were at 291 Elizabeth St in 1936, a building owned by W. T. Cottman, who was the Singer car distributor at the time. In 1940 Turner Bros vacated 291 - they had the building next door at 295 - and Cottman moved in to 291, so it bacame home of Triumph, Indian, and the Cottman Colt!
These 1930s efforts in badge engineering are not particularly important, but it's nice to get the record straight. As for whether imported bikes with Australian names should appear in a book on Australian motorcycles, I'm relaxed. If you came across a "Cottman Colt" or a B&W Hornet or a Utility JAP you won't find mention in a UK book!
Cheers
Leon