In actual fact with the Number 11 cab you really have to blame the Chief Inspector of Armaments at the Woolwich Arsenal in London. In late 1935, December I think it was, the CIS issued Specification Spec. 36 Parts I and II relating to War Department specifications for military vehicles. In the end this was amended and went to Spec. 36A/B/C/D and E, by spring 1939. The Department of National Defence elected to abide by Spec. 36 and thus slavishly adopted what was required as regards forward-control and detailed measurements relating to the driver's position. They also covered such aspects as ground clearance and cooling, but that's beside the point. Morris Commercial Cars and Guy Motors abided by the specifications and in many respects Sid Swallow of Ford, Windsor, adopted the MCC CS8/AT and Guy Quad Ant tractor cab designs (and tractor designs for the FATs) based on drawings sent through from London in fall 1939.