Inside the Chieftain's Hatch" AC 1 Sentinel

The_Chieftain:   In this case, it was more a matter of sheer curiosity. I've been spending more time than I want to reading up on the tank, and, being in the US, I've generally been confined to the operator's manual, what's on public websites, an old article in AFV News (or some such) and a copy of Fallen Sentinel I grabbed when I was in Melbourne four years ago. (Christ, have I had it that long?). Was wondering if I had missed something obvious/important. That PDF seems to have been one of them.