Hey Andrew,
Cool idea for a British "What if?" tank.
I've toyed with the idea of scratch building either the Heavy Assault Tank A33 or the TOG II with the Challenger A30's turret.
I was going to use Tamiya's Churchill and Cromwell/Centaur kits for starting points and add parts from other AFV's.
I noticed that you've used Tiger I tracks but where are those bogey wheels from?
The turret's also interesting, did you sculpt it or mold it yourself?
Anyway, it's a neat idea for something different to build.
Cheers
jjumbo