Some accounts say that the London, Midway and Scottish Railway built the thing to plans worked out by Chief Superintendent of Tank Design.
As the saying goes, "When you mix bureaucracy with anything you get bureaucracy ", ie when you mix engineering with bureacratic
requirements, you get bureaucratic requirements, when you mix science with bureaucratic requirements, you get bureaucratic
requirements.
It's the same with politics and anything. Reminds me of the old joke about the Camel being a Horse designed by a committee.
The Valentine was built to a spec requirement rather than a specific Dept design and was a private venture by Vickers. That may
explain why it was so much better. Private ventures have to come up with much better products as they depend on them for their
future - the De Havilland Mosquito is a prime example of that.
The design of the Sherman tank was done through the US ordnance design department. Although this was ostensibly a government
department it was an actual design run system where actual designers who knew what they were doing were tasked with making
vehicles that did specific jobs.
The best thing for the Sherman was these designers leaned towards what already worked (suspensions etc used on earlier vehicles)
as well as being open to influences from other countries designs, especially Britain and surprisingly, Canada. The M3 Grant was
already a sound designs the Sherman had many similarities. The main difference of course was the shifting of the main gun from
the hull to the turret.
The end result was the best all round tank of the war.