I'd be very surprised if the song is Danny Daniel, which as far as I know has never been called anything else, and in which Roseberry appears only as a passing reference.

There is a Legend of Roseberry Topping in Halliwell's Yorkshire Anthology (9 verses, no tune named). The story is essentially as given above: a Northumbrian princess dreamed that her infant would perish by water, astrologers confirmed that Prince Oswin would die by water when one and a half, the mother took him to Roseberry Topping knowing it was far from water but when, exhausted from the ascent, she fell asleep the child was drowned when a stream of water came out from under a rock. (Halliwell adds: "It is said this incident gave name to 'Osmotherly' (Os by his mother lay), a village a few miles distant").

If anyone's interested in the Halliwell ballad I'll put it up.

Mick