[1] St Marks Hosp, Wolfson Unit Endoscopy, Harrow HA1 3UJ, Middx, England
[2] St Marks Hosp, Intestinal Imaging Dept, Harrow HA1 3UJ, Middx, England
[3] St Marks Hosp, Polyposis Registry, Harrow HA1 3UJ, Middx, England
[4] Royal Free Hosp, Dept Liver Transplantat, London NW3 2QG, England
[5] Royal Free Hosp, Hepatobiliary Med Unit, London NW3 2QG, England