Quite a few Marks out there:
Mark McGuire (Deaf Shepherd)
Mark Dunlop (Malinky)
Mark Duff (ex-Capercaillie)
Mog (who taught me)
as well as Martin O'Neill, Johhny (Ringo) McDonagh, and John Jo Kelly

And by the way, Greg, Jim Sutherland has been hugely busy with La Banda Europa, writing film scores and othe major musical projects.