Crusader part 2 is out, the Chieftain is somewhat less than impressed with certain aspects of the interior :
Looks like the gunner is supposed to have a seat, or at least one is visible in the stowage sketches. Also a firewall, although photos show access doors suggesting it can be closed off but with a large curved opening, missing a plug? Given the presence of a 75mm breech ring and the sparsely populated interior, that vehicle is certainly an outlier, even for a museum tank.
I always thought that those two rectangles in the turret sides were just shuttered openings/pistol ports, but they're not, there's some kind of vision device fitted there. And Nick didn't tell us what they were!