I've been looking at my ancient and battered 5/- copy of the Penguin book of English Folk Songs - Guest, you may be interested to know that the shear board and scissors verses were both included in the version collected from Sarah Foster of Sedbergh. The notes on the songs say "In folklore, the poor tailor seldom plays a noble part, perhaps because his profession does not call for lustihood. 'Nine tailors make a man' says the proverb, and a popular children's rhyme tells of four and twenty tailors frightened by a snail. The amusing Benjamin Bowmaneer seems to perpetuate the folks' injustice to men of an honorable trade. Perhaps the song has a secondary, satirical meaning that eludes us?"

Of course cobblers got a similar treatment in folk songs too...