Well done Greg Stephens. The whole idea of 'English' folk music is about as absurd as the idea of a true born English person. This 'fact a fiction' was exposed over 400 years ago. Despite some peoples' attempts to exclude 'irish ' music ( but include Breton and Eastern European)in their 'English Music' sessions, hundreds of traditional tunes appear in the repertoires of players and singers from many communities, having been largely spread by travelling people. Of course, having found a foothold in a local community the song/tune would have taken on the characteristics of the local players, and probably a localised title ( Rakes of Mallow/Rigs of Marlow) but to suggest , e.g Smash the Windows/Roaring Jelly, or Garryowen/Walk of the Twopenny Postaman, or Lass o'Dallogill as EITHER 'Realy' English or Irish is ignorant beyond comprehension. To do so you would have to set the clock at a certain date, like Sharp and co often did, blissfully unaware of tradition and evolution.
The same can be said of the collectors who recorded 'traditional'musicians and attempted to ditinguish, in their repertoire, those tunes/songs which were traditional, and those that had come from 'sources' ( music hall, radio , sheet music etc).Jeez, they all started somewhere, some thought that if they knew WHEN and WHERE, the tune originated it wasn't traditional. sometimes called anon. Well, it is theoretically possible to discover the first edition of every song, does this mean that none of them are traditional?