Many thanks for everyone's help with these lyrics. The Wikipedia article references several songs including the Shave the Monkey one, but with no lyric link for it. There are lyrics to a number of other witchfinder general songs on Google, but the only Google link to these particular lyrics is to this thread. So for the sake of completeness, here's the consensus lyrics:

WITCHFINDER GENERAL
(Carolyn Sheppard & Bryan Causton)

He will find you, he'll come searching, innocent or guilty yet
He will ask and you must answer, condemned to die by Pyewackett

Are you listening Matthew Hopkins, are you sleeping sound
Can you hear us scratching from our graves in the ground
We're a widow and a wife, we are Reid and West
We are Clarke and Mills and our souls cannot rest

Lizzie Clarke was just the start, many more hung by her side
For not bleeding when you pricked us with a knife that cut no hide

Are you listening Matthew Hopkins, are you sleeping sound
Can you hear us scratching from our graves in the ground
We are four hundred strong, we are dead by you
We are lost to the church, to the devil we are due

Torturing the weak and feeble, townsmen paying you in gold
Feeding fever in the fearful, murdering the poor and old

Are you listening Matthew Hopkins, are you sleeping sound
Can you hear us scratching from our graves in the ground
You're the witch finder general, you are bold and strong
You are rich and respected, most of all you are wrong

He will find you, he'll come searching, innocent or guilty yet
He will ask and you must answer, condemned to die by Pyewackett

Are you listening Matthew Hopkins, are you sleeping sound
Can you hear us scratching from our graves in the ground
We're a widow and a wife, we are Reid and West
We are Clarke and Mills and our souls cannot rest

Are you listening Matthew Hopkins, are you sleeping sound
Can you hear us scratching from our graves in the ground
You're the witch finder general, you are bold and strong
You are rich and respected, most of all you are wrong