It's quite clear from the notes to the songs that the "county" arrangement was highly artificial (yes, I do remember the Lewes show...!) - and, to give credit to LEB & JAFM, they do mention other sources, variations and similar minutiae where they can.

What's particularly interesting from a musical point of view is the piano arrangement that's been provided for each tune. These, as a whole, reflect the late Victorian taste of the time. I had a crack at transcribing the piano chords for "Lazarus" for guitar, because I was intrigued by the very "churchy" feel of it all - no wonder Vaughan Williams used it for his "Variants on Dives and Lazarus" - and you can see what I made of it in Lazarus.

This is very different in feeling from some of the more robust versions of "Star Of The County Down"... by the Chieftains, say. :-)