Perhaps living in an era where stoning, punishment by loss of limb, crucifixion and none of the conveniences that he would be used to may be a deciding factor. One interesting thing is that Cat, Lister and Rimmer would be giants in relative terms if they visited an era such as that one. I'm not certain of the average male/female height, but if you look at doors in the UK still around from Tudor times, they are tiny! I always think this about TV/Movies - they ignore the fact that if anyone goes back in time a long way, they would all be WAY smaller... They should cast actors accordingly.