“Hi, Julian—over here!” I looked up from pushing my trolley in Marks & Spencer’s food department and saw a tall lady gesticulating at me. She was a little hampered in doing this as she had a plastic cup of coffee in one hand and a mobile phone clapped to her ear with the other. At first I thought I would take no notice. Julian is my name but I did not think I knew the lady or liked the look of her. But on second thoughts, which I later regretted, she did seem vaguely familiar, so I duly pushed my…