1. Pennine Acute Hospitals NHS Trust, Greater Manchester, UK
2. Division of Diabetes, Endocrinology and Gastroenterology, The University of Manchester, Manchester, UK
3. Honorary Senior Lecturer, Division of Diabetes, Endocrinology and Gastroenterology, University of Manchester, Manchester University NHS Foundation Trust, Neurogastroenterology Unit, Wythenshawe Hospital, Southmoor Road, Manchester M23 9LT, UK