Just for the record Roud number is 2757 and we now have 4 versions, the London broadside c1790
Canadian, Creighton's FS from S New Brunswick p131
Irish, in the Joyce ms
a ms version from Robin Hood's Bay c1870 (title Billy and Sally). The evidence is mounting for earlier version(s). The language in the SNB version is somewhat flowery and the rhyme scheme is abab unlike the others suggesting that this version harks back to the earlier version. It also has extra material not in the broadside.