Compared to the Light Tank Mk II the superstructure went further back.
The Light Tank Mk III used a Horstmann suspension with double springs that absorbed the rebound and shock of cross country travel.
Initially there was a Rolls-Royce engine with a Wilson gearbox. Some of these were replaced by Meadows engines. To tell the difference the Rolls-Royce had a silencer that was about half the length of the track guard and a tail pipe with a fish tail. While the Meadows had a short silencer that had a straight tail pipe.
The Light Tank Mk IIIs used two different types of turrets, the Mark I or a Mark II.