1. Worthing Hospital; Department of Colorectal Surgery; Western Sussex Hospitals NHS Trust Worthing West Sussex UK BN11 2DH
2. Royal Free Hampstead NHS Trust Hospital; Department of Vascular Surgery; Pond Street London UK NW3 2QG
3. University College London; Research Department of Primary Care and Population Health; Royal Free Campus, Royal Free Hospital Pond St, Hampstead London UK NW3 2QG
4. Royal Free Hampstead NHS Foundation Trust; Department of Vascular Surgery; Pond Street Hampstead London UK NW3 2QG