1 National Centre for Bowel Research and Surgical Innovation, Blizard Institute, Queen Mary University of London, London, UK. Electronic address: c.h.knowles@qmul.ac.uk.
2 National Centre for Bowel Research and Surgical Innovation, Blizard Institute, Queen Mary University of London, London, UK.
3 Pragmatic Clinical Trials Unit, Blizard Institute, Queen Mary University of London, London, UK.
4 Florence Nightingale Faculty of Nursing and Midwifery, King's College London, London, UK.