The reaction of LiH with the oxy-chloride Sr3Fe2O5Cl2 initially leads to the topotactic deintercalation of oxide ions and the formation of Sr3Fe2O4Cl2 containing sheets of pseudo square planar Fe(II). Reaction at higher temperatures with either LiH or CaH2 leads to further reaction and the formation of a new phase which has undergone a ~20% expansion parallel to the structural stacking direction. It is proposed this new phase is formed by the anion exchange of chloride ions for hydride ions driven by the formation of LiCl from LiH in a metathesis reaction. We propose to collect high resolution neutron powder diffraction data to fully characterise the structures and magnetic ordering of both new phases.