Colin,
The turret bulge issue looks to be solved, but I think there has been some confusion as to the extractor fan.
Looking again at the drawings, I note that on the page that gives multi view drawings of the turret, I now see the bulge detail is totally different (cannot quote a number).
That drawing is for the Mk VI C, as is probably that one showing the fan.
The Mk VI C had the 15mm and 9.2mm BESA's fitted.
I have one photo of a captured Mk VI C from a Japanese magazine which shows this cover, and is most definitely for extracting fumes. So I think we have mix of drawings.
George.
