Excellent! Having "finished" the Ss, I'm pleased that the entries for Simplex and Star seem to fit in with the rego data:
SIMPLEX
In 1936, 1937, and possibly 1938, Turner Bros, 291 Elizabeth Street, Melbourne, Victoria, advertised Simplex Villiers motorcycles with 125 c.c., 148 c.c., 196 c.c., and 250 c.c. engines. The Simplex used a Burman gearbox and was said to be ‘built to suit Australian conditions.’ Although British made, the Simplex name was likely used only for export. [OK]
STAR (3)
In 1938, Finlay Bros, 322 Elizabeth Street, Melbourne, Victoria, advertised Star Villiers motorcycles using the 148 c.c. Super Sports engine. The Star was likely British made, with the Star name used only for export. [OK]
If you give me some likely dates for "Speed" I will have a look in the newspapers. "Speed" is one of those words that is difficult to search for as it is everywhere - better to look for things that are easier to find like T is for Trescowthick or Treblig. Maybe the 49/ Speed engine numbers means that it's post WW2.
Cheers
Leon