Idlers and Scivers (sic) by Keith Marsden has the chorus

But we're knocking at the door, knocking at the door,
And a penny in the poor man's hat will no longer do.
They'd better open wide and let us come inside
For the knocking's nearly over, then the door's coming through!

When we used to sing it we knew the song as "Knocking", and that's how we indexed it.