I hate to rush into a string that has such a potential to get hairy, but Lesley makes a good point up yonder about the issue of duplication. A good example I know of is The Cruel Sister, and its varients. I've encountered at least four versions, one English, one Irish, and two Scottish, the best in my opinion being of the latter type and recorded by Old Blind Dogs. Where to put them? I would say that it makes sense to me to have a category called British Isles Music and lump them all together, but I won't: I hate to start up a political melee in such surroundings.