_Songs From The Front and Rear_ edt Anthony Hopkins, Hurtig Publishers/Edmonton 0-88830-171-5 has a model verse for this song.

Oh, knees up, Mother Brown,
Knees up, Mother Brown.
Come along, dearie, let it go,
Ee-I-Ee-I-Ee-I-O.
Its your bloomin' birthday,
Lets wake up all the town,
So, knees up, knees up,
Don't get the breeze up,
Knees up, Mother Brown.

This, they claim, is the one universal verse to all the songs. I know there are many more verses but I cant remember them off hand.

bo hope this helps.