Short & sweet
"Bon(n)y sweet boy" is a version of "Robin is to the Greenwood gone", which I posted as part of a compendium of "Robins", which you can read here.
You can view and download the arrangement here.
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SOURCE: Thomas Robinson, 1603, The Schoole of Musicke (f. M2/2).
Facsimile at: https://ks4.imslp.net/files/imglnks/usimg/9/9a/IMSLP247275-PMLP401021-Thomas_Robinson_School.pdf.
See also “Robin is to the Greenwood Gone”, f. I2v