I can picture the scene in my head, and it sure looks like Tolkien - maybe a little older, but you would think a notable like that would have been credited with an honorable mention for a cameo appearance.

Thanks for replying John. The episode was shown on one of our chanels here in the UK this weekend and I did a double take when I saw it. Having paused the programme and bringing Tolkein's pics up on the net, I'm more than sure it was him. Given that the episode was filmed and aired about a year before he died in 1973, the person certainly looked about the correct age and the reason why there were no credits to the effect? Well, I believe that if no words are spoken by an extra then there is no credit seen in the start/end titles to that particular person but I could quite possibly be wrong there.

As to why Tolkein, if indeed it was him, should be asked to play an extra is anyone's guess but could be down to the director, producer, Peter Falk or some other key person being a fan of his work; who know's? Certainly something to ponder on.