Contrary to an earlier post, the clerk at MacPherson's is clearly referred to several times in the dialogue and also in the end credits as Meekie not Mitty. Meekies have been resident in Scotland since the 19th century.
In 1956 Hecht-Hill-Lancaster Productions announced plans to film James Thurber's "The Catbird Seat" with a screenplay from George Axelrod.
One character is referred to as Mr Mitty, a small homage to James Thurber, writer of the original story who also wrote The Secret Life of Walter Mitty.