Here's Douce Ballads 3(27a):
http://ballads.bodleian.ox.ac.uk/static/images/sheets/20000/15601.gif
Edition - Bod18681
Imprint Names: Aldermary Church Yard
Imprint: Printed and Sold at No. 4, Aldermary Church Yard, Londo
Title: Fair Margaret's misfortunes; or, Sweet William's dream on his wedding night, with the sudden death and burial of those noble lovers

First stanza: As it fell out upon a day
Two lovers they set on a hill;
They set together a long summer's day
And could not take their fill.

It has "set" instead of "sat". I'm not sure what broadside Child used.

Richie