It's actually Nordic. Comes from the word 'lobskause', which became lobscouse when it came to the ports, mainly in Liverpool and in some South Wales towns and gave the words 'Scouser' and 'Lobby' their roots. It has all sorts of different variations and like you say BS it has an affinity with mining and working class backgrounds as ingredients were cheap and easy to come by.

or why not go to M & S

We havn't got one, there's an M&S in Glazebury, but that's a completely different animal.

maybe should read S & M

Or more likely B & M