Indium-labelled octreotide study (including single photon emission tomography when undertaken), if:(a) a gastro-entero-pancreatic endocrine tumour is suspected on the basis of biochemical evidence with negative or equivocal conventional imaging; or(b) both:(i) a surgically amenable gastro-entero-pancreatic endocrine tumour has been identified on the basis of conventional techniques; and(ii) the study is to exclude additional disease sites (R)