Traditional enough? A song's either traditional or it isn't; and you can accompany it however you like as far as I'm concerned, as long as it doesn't get in the way of the song. As for the performer being traditional enough...

I just checked, and it turns out that Peter Bellamy and Tony Capstick were almost exactly the same age - they were born about six weeks apart. (If the stupid buggers had stuck around they would both have been 70 now.) When they invent time travel, a gig by one of those guys is going to be my first stop - but I'd have to toss a coin to decide which one. Preferring traditional songs doesn't make you deaf to everything else.