This proposal is part of a broad programme of collaborative research between RAL / Oxford and Unilever, using predominantly scattering techniques to investigate the nature of surfactant mixing at interfaces and in solution. This proposal focuses on the mixed anionic surfactant sodium alkyl benzene sulfonate, LAS, with nonionic surfactants. When the symmetrical isomer of LAS is mixed with C12EO8 and nonionic with longer EO lengths small globular micelles are formed. In the presence of Ca2+ a richer phase behaviour is observed, with a transition to vesicles or a mixed vesicle / micellar phase. We request here SANS beam time on LOQ to explore further this novel behaviour. In particular, we wish to investigate the role of different nonionic cosurfactants of different preferred curvatures, and the impact of different LAS isomers.