[1] London North West Healthcare NHS Trust, Dept Gastroenterol, Harrow, England
[2] UCLH, Gastroenterol, London, England
[3] Kings Coll Hosp London, Inst Liver Studies, London, England
[4] St Marks Hosp, Harrow, England
[5] Acad Inst Wolfson Unit Endoscopy, Harrow, England
[6] Kings Coll Hosp London, London, England
[7] Aberdeen Royal Infirm, Aberdeen, Scotland
[8] Kings Coll Hosp London, Dept Gastroenterol, London, England