Some tentative research in the Commercial Motor archive reveals that the 1908 French Antarctic expedition led by Charcot was apparently the first to take motor vehicles. These were three powered sleighs, fitted with air-cooled 40hp De Dion Bouton engines 'of the 1901 type'. His account of the expedition, Autour du pôle sud, was published in 1912.
Scott's motor sleds were indeed built by Wolseley:
"The most unusual feature in the Wolseley motor sleigh, one of which is, as we reported last week, on order for Captain Scott's Antarctic expedition, is the manner in which it is propelled. An axle is fixed at each end, and carries toothed wheels which, however, do not touch the ground. Endless chains run over these wheels, and these chains pass underneath the surface of the sleigh-runners; each chain is fitted with small platforms bearing cross strips or "spuds." The chains are driven by the toothed wheels on the rear axle, the effect being to propel the sleigh forward. The grip on the snow is a very powerful one, and, in addition to propelling itself, the sleigh will also draw a heavy trailer, even under the worst conditions of melting snow.
In order to economize fuel, the engine is a comparatively-small one of the air-cooled type; it is capable of developing sufficient power for all re quirements. A gearbox and clutch are provided, and the petrol tank is mounted above the motor. Two changes of gear ratio are provided, and an average speed of from 3 to 4 miles an hour is expected. The design of the sleigh is the outcome of careful experiments, every detail having received due consideration." (Commercial Motor, 20th January 1910)
There's a full-page feature here: http://archive.comme...h-april-1910/16
"Following the purchase of Wolseley motor sledges for Captain Scott's South-polar Expedition, which we reported and illustrated in our issue of the 7th April last, it will interest many readers of this journal to know that the Wolseley Tool and Motor Car Co., Ltd., of Adderley Park, Birmingham, has received an order for three motor sledges for the use of the German Antarctic Expedition. They will in principle be the same as those which were supplied for Captain Scott's expedition, and it is not inappropriate that we should reproduce photographs of the original sledges when undergoing their trials in Norway; these views are now published by the Wolseley Co. as picture postcards." http://archive.comme...ews-and-comment