In this work, we will investigate the structures (crystallographic and magnetic) of Mn5VO8 and a range of Fe containing perovskite oxide fluorides. In terms of the former, this phase has been shown by X-ray diffraction to crystallize in a novel structure which can be derived from a ccp of oxygen ions, with Mn3+ and Mn2+ located on different crystallographic sites. the aim here will be to determine the magnetic structure of this material. In terms of the oxide fluoride system, we aim to extend our prior studies of cubic systems, e.g. BaFeO2F, to a range of non-cubic systems, including BaxBi1-xFeO3-xFx, La1-xSrxFeO3-xFx, and hexagonal BaFeO2+xF1-x. The neutron diffraction studies will allow us to gain further information concerning the F site (through consideration of bond distances/bond valence sums), as well as changes in structure (crystallographic and magnetic) across each series.