I've been into Bluehorses for several years. I used to post on their forums about mandoplanks.

However I was listening to a program on Radio 3 the other day about the evolutions of Irish music, mostly from the 1800s as Irish classical music came out from under allegedly colonialist influences (also some recordings of McCormack and O'Sullivan) and the historian definitely spoke of the influences of early religious music on sean nos. I was only half listening though, so cannot be clear exactly what he said.