Diagnostic yield from symptomatic gastroscopy in the UK: British Society of Gastroenterology analysis using data from the National Endoscopy Database by Beaton, DR, Sharp, L, Lu, L, Trudgill, NJ, Thoufeeq, M, Nicholson, BD, Rogers, P, Docherty, J, Jenkins, A, Morris, AJ, Rösch, T, Rutter, MD