Probably the first example of a "folk singer" using a guitar that I can recall as a child was a man whose name escapes me, but advertised himself as singing "songs to a small guitar" and appeared ,doing just that,in a Robin Hood film ! I think he did (but not in the film !) a recording of "The Owl & The Pussycat". Also,we had the "Tonight" programme on English TV,which gave us regular "doses" of Robin Hall & Jimmy McGregor,an early "act" to use a guitar in a "folk" style,but otherwise,there was somewhat of a paucity of guitar-accompanied "folk",other than a few occasional Radio examples of Burl Ives or Woody Guthrie.
                The Genesis of any kind of recognisable "English Folk Guitar" style per se, was probably an amalgam of the styles,tunings,and playing methods of the likes of such divers players as John Renbourn,Alexis Korner and,of course,Davy Graham. In which case,English Folk Guitar history is not really very old at all !!