Complex sentence: One guest complains that her prawns are "off," provoking an argument between Basil and her husband, because she has eaten half the dish but they wish the starter to be deducted from their bill.
Split into simpler sentences: One guest complains that her prawns are "off". This provokes an argument between Basil and her husband, because she has eaten half the dish but they wish the starter to be deducted from their bill.