Well, are you trying to figure out the actor's age during the series (given above), his age now (also given), or the age the CHARACTER was supposed to be in the story? That was never actually given. He did have his birthday in "The Canterbury Crock," in which he only admits that once you get to his age you don't make a big deal out of it, but that's the extent of it. Probably easiest to go with something an approximation of Ben Jones' actual age.