Another vote for a plastic Comet from me.
Pinky - you're right, the hull hatches are very small - they are L-shaped in cross section but getting in or out required a similar technique to getting into a car that's had the doors welded shut, you don't go straight down but angle yourself in, (TheChieftanWoT - on YouTube) demonstates this quite well on his excellent walkaround of Bovingtons Comet (he's also 6'+ so is a good comparison). This is par for the course on British tanks, seeing (essentially correctly) that any hole in the hull as weakening it's integrity.
Both US & German AFVs had more generously proportioned interiors, with notable exceptions such as the Jagdpanzer 38t which would surely win hands down in the uncomfortable stakes.