The version I know and sing is very different... I'm not sure where it's from - anyone who cares to know it's probably in the sleeve notes of Bare Bones (Tony Rose) but I haven't got a copy to hand right now. I'll put it down in case anyone is interested -

It's whispered in the kitchen, it's whispered in the hall
oh The broom blooms bonny, the broom blooms fair
that The king's daughter goes with child to her brother
And they'll never go down to the broom anymore.

He's ta'en his sister down to his father's deer park
oh the broom etc
With his yew-tree bow and arrow slung fast across his back
and they'll never go down etc

And when that you hear me give a loud cry
Shoot from your bow an arrow, and there let me lie

And when that you see that I am lying dead
Put me in a grave with the turf all at my head

And when he has heard her give a loud cry
A silver arrow from his bow he suddenly let fly

And he has dug a grave both long, wide and deep
He has buried his sister with their babe all at her feet

And then he has gone back to his father's own hall
There was music and dancing, there were minstrels and all

Oh, Willie oh Willie, "What gives thee in such pain?"
"I've lost a sheath and knife, I will never find again"

"there are ships of your father's a-sailing on the sea
that'll bring as good a sheath and knife unto thee"

"there are ships of my father's a-sailing on the sea
but such a sheath and knife they can never bring to me"

same story though.

xLx