The Catnach version I mentioned is actually a version of I Am A Besom Maker (Roud 910) as opposed to Buy Broom Besoms (Roud 1623). There are plenty of broadside versions at the Bodleian and it was collected by several collectors (Baring-Gould, Sharp, Vaughan-Williams at least). Looking at the some of the collected tunes, the verse is usually different from Buy Broom Besoms, but the chorus has a similarity. All examples seem to be later than Buy Broom Besoms; I still suspect that the chorus of BBB was adapted to the new song - any opinions, Steve?
Here's the text from Holloway and Black.
Mick Buy Broom Besoms
Printed and sold by J. Catnach, 2, Monmouth Court, 7 Dials.
Sold by T. Batchelar, 14 Hackney Road Crescent; Bennett, Brighton, and Pierce, Southborough
I am a besom maker, listen to my tale, I am a besom maker, lives in yonder vale, Sweet pleasures I enjoy both morning, night and noon, Going over the hills so high a gathering of green broom.
CHORUS Come buy my besoms, besoms fine and new, Bonny green broom besoms, better never grew.
One day as I was roving, over the hills so high, I met with a rakish squire, all with a rolling eye, He tipt to me the wink, I wrote to him the tune, I eas'd him of his jink, a gathering of green broom
One day as I was turning to my native vale I met Jack Sprat, the miller, he asked me turn tale His mill I rattled round, I ground the girls so clean I eas'd him of his jink in gathering broom so green
One day as I was turning to my native cot, I met a buxom farmer, happy was his lot, He plough'd his furrows deep, & laid his corn so low He left it there to keep her, like green broom to grow
When the corn grew up to its native soil, A pretty sweet young baby soon on me did smile, I bundled up my besoms and took them to the fair, And sold them all by wholesale nursing now's my care.