Metchosin 12.99: Sorry I'm late. I think the 'dirty nipper' verse is from another song, 'The Good Ship Venus' in which the cabin boy was, indeed a dirty nipper who 'stuffed his arse with broken glass and circumcised the skipper'.

It may have been woven into a parody of 'Tom Bowling', but it is difficult to see how it could- er- be made to fit..