Excuse my ignorance
Well, since you asked nicely - OK.
(
Just kidding, of course.
)
I've known some siblings who look very much like each other, but not THAT much, unless they were twins.
By that premise we could say that since Jeff Clark and Ned Stuart look so much alike, they couldn't possibly be anything but twins. (What a horrifying thought!
But it might possibly explain why both seemed to behave so equally irrationally.
)
Well, OK - that's taking your premise to an absurd conclusion because Jeff and Ned weren't related (so far as we know, anyway). But the point is that as part of our original discussion we'd ruled out Don Briscoe having played both Tom and Chris as a factor in determining whether or not they were twins simply for the fact that they would look identical and instead relied solely on how the show's dialogue described them. It would have been perfectly natural for the show to have explained away the brothers' resemblance by explicitly stating that Tom and Chris were twins. But the fact that they didn't and merely inferred that they looked remarkably alike might actually be more telling evidence that they weren't twins.