Complex sentence: Brough's was a family owned retail chain serving Northern England which was a British pioneer of the self-service model whereby customers took goods from open shelves and paid for them at a check-out desk rather than being served at a counter.
Split into simpler sentences: Brough's was a family owned retail chain serving Northern England. It was a British pioneer of the self-service model whereby customers took goods from open shelves and paid for them at a check-out desk rather than being served at a counter.