Try www.yorkshirefolksong.net and click on the song 'The Lady of York'
Read the Provenance section. Here is a much reduced version of 'The Cruel Mother' collected from gipsy children in the late nineteenth century. The more recent Irish/Liverpool burlesque may have evolved from such a version. To suggest that any version of The Cruel Mother, even the 16th century version, is based upon any real event is pretty ludicrous.