Well, remember, you Aussies put twin 25 pdrs or a 17 pdr in a turret that had the same diameter turret ring as the Lee. The Sentinel turret in that configuration sure wasn't comfy, but everything's a tradeoff. Theoretically, you probably had the room to put a 17 pdr in the Lee hull and a Sentinel turret with another 17 pdr on top of it, but that would be pretty silly. Not as silly as a TOG, but then again, few WWII tanks were.
Cheers,
Logan