I've got a soft spot for the Mark 1:
Possibly down to being greatly impressed one day at Bovington by Pz. I,II,III,IV,V,VI,VIb all parked in a row with the Jagdtiger at the very end, at how much change in size and weight could occur over only 5 years.
The Mark 1 is shorter than the barrel alone on some of the later vehicles.
Cheers,
Adam