Neutron reflectometry (NR) is a very powerful technique for the study of thin layers. It is able to measure composition, thickness and roughness and is a very penetrating technique. One of the drawbacks when using NR is the loss of phase information in going from real space to inverse, or q space. In order to develop the phase retrieval approach at ISIS we would like to use this technique to unambiguously probe the composition profile for ideal and more complex real polymeric systems with many layers. An interesting possibility is to extract the reflection coefficient by using a magnetic reference layer and polarised neutron reflectometry (PNR). We shall also analyse the data in a conventional PNR manner (no phase retrieval) to look at any discrepancies between the methodologies. Once this route is established and the transform matrix route confirmed we will move to more complex systems