A bap is a scottish term for a normal bread roll, no idea what a barm is though?
I live in that awkward no-mans-land of the north-west when it comes to describing those small, ovoid bread products.
Over the centuries, we’ve absorbed various onslaughts from the north, as Glaswegians descend on Blackpool with their deep-fried spam baps. We’ve repelled several advances from those tight-fisted ****s to the east, with their “tea-cakes”, and we’ve welcomed exotic travelers from the south with their cobs and breadbuns.
So most terms are acceptable in this part of the world, but if it’s floury it’s a bap, and if it’s crusty it’s a cob.
I hope that clears things up.