Ive been thinking about this for a little while & i came to the conclusion that James May is very probably ISTJ (bear with me cos ive only been into MBTI for a few months). Think i saw some site saying Jeremy's an ESTP but i think i'll go along with your ENTP. Not sure enough about Richard, though. Have you read any of his Daily Mirror columns online? Maybe that would shed some light?
I do know from a blog from the show's producer that Jeremy goes to most publlic events with much reluctance, preferring to be with family & friends. Apparently James is a case of what you see is what you get. I'll put up a link for one of Richard's columns but no idea if they'll help. Let's hair it for the real men - mirror.co.uk
Having read part of Richard Hammond's autobiography, I reached the conclusion that he is an ESFP. S is because as a child he got immense pleasure from taking things apart and putting them together again, and as a young man would spend hours (even in the freezing cold) fiddling with his car's mechanics. The man has got to be S!
P because he bends or breaks rules.
E because he's presenting a programme on TV! He shows little sign of introversion. Also presented a talk show.
F because he is driven largely by his feelings and enthusiasm for various projects
Clarkson I think is an ENTP.
May is IXTP. How many TJ males would have long hair?
I did think for a while that Clarkson was an ENTJ, not just because it peeved my father to theorise that he was the same type. ENTP sounds about right though, eh has the whole INTJ thing of not caring what you think combined with the Loser habit (a little too in your face competetive for an INTJ).
I'm not so sure about Hammond though... there seems to be another persona behind those eyes and he's a little twitchy on camera.. I'd not put it out the realms of possibility that he's an introvert.