Which 'Pepys Ballad Collection Facsimile' is that? You don't give any publication details. I can confirm, though, that a facsimile can be seen online at The Pepys Ballads (University of California-Santa Barbara, prepared from photographic images of the collection held at the Pepys Library, Magdalene College, Cambridge):
I'm not sure why Wardroper felt the need to change the way a few words were spelled (the original is perfectly easy to understand); equally, "thurg" misses the point that applying modern, subjective aesthetic judgements to historical material is anachronistic and irrelevant.
For a detailed discussion of the song-family and its origins, see Robert S Thomson, 'The Frightful Foggy Dew' in Folk Music Journal, London: EFDSS, Volume 4 Number 1 (1980).