You are right about the pressed steel Bowden levers Ian. But at least some were fitted with the solid brass levers as can be seen from this page from contract C14499 (1941)
Then the pressed steel levers were replaced from frame 39551 to the standardized Amal levers. Then post war they went back to the pressed steel levers but the air and mag levers had a knob on the end instead of the earlier flat end.
I've only learnt all this by consistently getting it wrong over the years:confused: Ron