And the version in The Oxford Book pof English Verse has 25 verses - but no indication where they came from.

Mind I think the distilled shorter versions that jump right into the middle of the story without any explanations are more powerful. Folk wisdom.

As for "gardens planted to remind people of Catholic doctrines, with flowers (eg lilies) associated with the Virgin Mary" - my wife remembers, when she was a child after the war in London, she used to make "grotters" with shells and glittery things by the side of the pavement. Only years later did she realise they were actually "grottoes".