My 'Observer's Book of Horses and Ponies' (published about 1958) says of the Australian Waler..."The foundation stock of the Waler was of Dutch and Spanish origin, with the oriental horses, the Arab and the Barb as the ultimate ancestors. These original animals were small, and as the settlers had great need for riding horses and wanted the best, pure Arabs and English Thoroughbreds were imported.....It has been asserted with some justification that between Waterloo and the Crimea, Australia possessed probably the best saddle horse in the world, and during that period began to supply cavalry and artillery troop horses to India. Racing, which first appeared in Ausralia in 1826, further helped to establish the Australian Horse, the breeding of which has spread in the natural course of time...but the name 'Waler' still applies to them all......The Waler has always been noted for jumping in his own country, high-humping competitions being a specialty at all shows......Australian horses are all shapes and sizes, including besides the Waler a draught-horse breed developed from three English strains - Clydesdale, Shire and Suffock Punch." There is more, but I think the above covers the main points. Hope it helps you.
Wendy in Western Australia.