JTT, I don't know what kind of bus you travel on regularly but that kind of story seems to have vanished on Merseytravel, although I'm sure I remember hearing a long while ago one old lady reassuring a very pregnant and anxious young girl "Don't worry; it'll all come out in the end!"

From all I can gather, Dan Leno varied his patter a lot and improvised in collaboration with his audience - a lot like Frankie Howerd - so the postman could have easily become a milkman or a coalman in different renditions.