Interesting topic. I learned to drive on a grey Ferguson, when aged ten.
Wikipedia mentions that the Antarctic Expedition took seven TE20s, four petrol and three diesel:
A fleet of seven Ferguson TE-20s was used on the 1955–58 Commonwealth Trans-Antarctic Expedition which was led by Edmund Hillary. Four petrol-engined and three diesel models were used. Some were supplied as half-tracks, with steerable front skis, whilst others of the New Zealand team were fitted with an extra wheel on each side and full caterpillar tracks, developed by the expedition in the Antarctic. In both cases,