The Mayes' group at UEA is world-leading in investigating core-shell nanoparticles as a promising format for 'synthetic antibodies', based on molecular imprinting. One of the fundamental issues in the understanding of these materials is knowledge of the sizes of these particles and the thicknesses of the shells. The lenght scales of relevance (50-100nm) fall outside the range of traditional SANS. The spin-echo SANS possible with the new instrument OffSpec gives us access to these length scales. The present application is to explore this technique to measure the dimensions of the coreshell nanoparticles that we produce at UEA.