LMS advised a return to riveted construction due to doubts about the strength of the welds, and rather than risk delays due to a lack of welders, this was accepted. The welded design used two layers of armour plate, the inner being of steel that would weld readily without losing its properties. This two-plate system was retained when the design reverted to riveted construction. The use of riveted construction, the use of steel wheels instead of the intended aluminium and an increase in armour specification to at the front of hull and turret increased the weight to a level where the tank suspension was at maximum load, leaving no room for later development of the design.