The retail guru works with four businesses to help improve the quality of their customer service. At a family-run convenience store in Burnham, Buckinghamshire, she's shocked to see how staff behave when they don't know they're being filmed. Too much clowning around means out-of-date food is being left on the shelves, so Mary takes supervisor Dean and his team to a Michelin-starred restaurant to show them how to work well together. She also wants owner Keshu to rethink the products he stocks and give his savvy daughter Ash more responsibility.

• Mary Portas