In plasmas with an optimised current profile, where Internal Transport Barriers (ITBs) can be generated, the best performance has previously been found on JET for plasmas with low target density, low triangularity and a divertor plasma configuration chosen for maximum pumping. In contrast, on DIIID, the highest performance for plasmas with ITBs is found with strong shaping. The Advanced Tokamak regime for ITER requires high density, and assumes high triangularity. This paper describes systematic experiments which have recently been performed on JET on the effect of plasma shape, target density and divertor pumping in plasmas where the target q profile exhibits strong shear reversal obtained by the application of Lower Hybrid Current Drive (LHCD) during the pre-heat phase [4 and 5].