According to a Polish article by T. Basarabowicz in "Militaria i fakty" 2/200, the first Australian tanks were ten Mk.VIa, delivered in 8/1937 only (also Osprey NV217 "British light tanks" says 1937)
Mk.VIc and earlier models were given only n 1940 in North Africa.
Osprey NV217 says, that six Mk.IIb were given to the 6h Divisional Cavalry Rgt in 10/40.
289 Rover - according to
http://www.diggerhistory.info/pages-.../lac-rover.htm and
https://en.wikipedia.org/wiki/Rover_Light_Armoured_Car , delivered only from 4/42
Possibly a better name would be Rover LAC.
Wikipedia and
http://www.tanks-encyclopedia.com/ww...r_light_AC.php claims, that armour was up to 16 mm in front, crew was 5, and speed was up to 80 km/h