Am currently watching Mind of Evil from Jon Pertwee's run. About five minutes in Jon's Doctor takes umbrage over being called 'not a scientist' and starts to say "I've been a scientist for thousands--!" then cuts his sentence short.
I can't decide whether it got cut short because the Doctor was reigning his temper back or because Jon remembered his character was supposed to be in his hundreds....
Did the show ever state how old he was supposed to be during Pertwee's reign? Recall that Tom Baker's was in his 700's.
Edit: Oh wow. Watching that Mind of Evil episode is starting to get creepy. In one scene they suggest that the Doctor's phobia is fire. Considering the later Time War.... *gulp*