Complex transition metal fluorides are of increasing interest to the solid-state chemistry and physics communities due to the diverse range of physical properties they exhibit. In contrast to the analogous oxide phases, complex transition metal fluorides tend to be anion rich (thus favouring lower dimensional crystal structures) and also contain transition metal cations in lower oxidation states than analogous oxides, giving us access to different electronic and magnetic lattices. Recently we have prepared two novel mixed valence transition metal fluoride phases, namely K4Fe3F12 and Ba3Mn3F14 which exhibit unusual complex magnetic behaviour. We propose to collect neutron powder diffraction data from these samples to investigate the complex magnetically ordered structures these phases adopt.