John in Brisbane

Would that be "Fair Fat and Forty" ???

I'm not sure if it's the same song where the guy says that she is so fat that he has to leave a chalk mark on her to know where he began.
I'm desperately reaching way way back into my memory to recall this one. If I come up with more I'll come back.

"I met a man coming the other way, over the mountain"

Then there was a Kenneth Horne (?) piece sung to a well know tune - so well known that I don't know the title:

"I've got a girl who's mighty sweet
Big blue eyes and sweaty feet
Her name is Isabel Malone
She tips the scale at twenty stone"

Thinking about it the tune was the signature tune for a popular radio series "Dick Barton, Special Agent"