Andy Irvine is a wonderful harp player. He plays if "backwards", and by that I mean he plays with the low notes on the right, I think he may also play it blues style, with the emphasis on the draw notes. I'm not 100% sure, but listening to him play I get the feeling that he plays 2nd position, ie, when he plays in E he uses an A harp, likewise a D, when he plays in A, but don't quote me on that one.