Yes, I somehow missed Malcolm's posting! As to the real story, there are broadsheets going back to 17th C and probably earlier,'The lamentable ditty of the little Mousgrove, and the Lady Barnet' printed between 1658 and 1664 is similar in places to the Nic Jones version, and Lady Barnet clearly issues the invitation.
You can find it online in the Bodleian Ballad Library here, I hope
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