After watching series note that the leading vehicles in opening convoy sequence are pretty much all the 'Brit' trucks used throughout in various guises and locations.
Leading vehicle is a Humber 8cwt followed by two CMP 3 tonners first with an oh so desert war early cab , second has a strange cab with sloping back windscreen which makes it very obvious in back scenes in various locations. Then there is a LRDG Chevrolet disguised with canvas cab and tilt , then another Humber 8cwt , then two Bedford MWDs , then another LRDG Chev in disguise then lots of REO 6X6s.
Craig