Strawberry Fair was collected by S Baring Gould but it appears he "sanatised" it. It can be found in "Songs Of The West". Sadly my copy is missing one page any yes, it is the page with the words to SF.
Here are his notes anyway:
Melody taken down from James Masters. This is a very old song. It is found with music in "Songs and Madrigals of the 15th Century," published by the Old English Plain-Song Society, 1891. The ballad was recast "Kytt has lost her Key", which is given by Dr Rimblaut in his "Little Book of Songs and Ballads gathered from Ancient Music Books," 1851 p.49. We have been forced to re-write the words, which were very indelicate. The air was used, in or about 1835, by Bueler, a comic song writer, for "The Devil and the Hackney Coachman"-
"Ben was a Hackney coachman sure, Jarvey! Jarvey - Heare I am your honour."
I have never found a singer who had any knowledge of Beuler's song, but all have heard "Strawberry Fair," and some men of sevent or eighty years say they learned it from thier fathers.
Lanfranc had promised to post the words in this thread but I haven't able to find them in Mudcat.