Take a look at the original broadside for rigs of London Town. It's in heavy Cant and deals with similar story lines.
With respect I think that the modern usage of the 'Brush' motif may have been rationalised from the 'Pick Pocket Eloquence' that sired it.
This is not always the case of course. The word Peter, is still used to represent a box, but mainly used as a slang word for a Prison Cell.
The 'Buy a Broom' song was certainly rationalised by any number of singers. Taken at face value, there is no problem, but further investigation suggests the story was a darker one. Despite Tim and Maddie's album notes the song has nothing to do with Gypsies by the way. Gypsy Folk do not sleep around then or now.