Rolls, baps, cobs etc are different shapes of bread they are not names that are location specific. I can never understand the confusion here ... you only have to look at the shape to see what to call them. Rolls are sausage shaped. Baps are large circular squashed things and cobs are what baps would have looked like if someone hadn't squashed them ... whats the problem?? A "round" is slang for one slice of bread not a sandwhich. If a sandwich is made from "one round" if would be folded or cut into two. A butty is just slang for a sandwich there is no difference.... whether it be buttered or not... or even "margarined" if there is such a word.