Found a few interesting photos of tank mock-ups on the IWM website, some of which were new to me.
http://www.iwm.org.uk/collections/item/object/205249665 This first photo is a well-known one of the mock-up for the original design of the Mk V. I include it for reference with the next photo, which I had not seen before - showing the front of this mock-up:
Subject two is the Mock-up for the aborted Mk VI heavy tank; the front quarter view is well known, but here is a rear quarter view, showing the shallower slope of the track return as it climbs to roof height. It also shows how the rear corner MGs would have covered the area behind the tank:
http://www.iwm.org.uk/collections/item/object/205249626 Both pics are much the same, but I've put links in for both in case you think one is better than the other.
Item three is a rear view of the Medium D mock-up. Side, front, and front quarter views are well known, but this should be less familiar; you can see the ducting for the radiator fan wrapped around the cardan shaft (prop-shaft):
Another Medium D pic, but this time from inside the mock-up. It's a little close-in to get the best feel for the interior, but it does give the impression that it would be quite cramped in action.
In case it's not clear what you're looking at, at bottom left is the open right-hand side door: the orientation of the photo is looking towards the right and rear of the fighting compartment.
At the bottom centre is a rack for boxes of MG ammo, presumably stretching the full width of the hull; above that is a step or footrest for the driver-commander, with his seat on the shelf above that.
On the left, the sloping panel is the underside of the mud chute, with the narrow darker plank of wood above it running next to where the upper track is outside. Immediately above that is the right-hand turret "sponson", with the back end of a Hotchkiss MG in the top left corner.