Unusual total conductivity behaviour at high Ba contents may be attributed to a change in conduction mechanism at high tempertaures, structure change or phase evolution/segregation. Conventional laboratory measurments do not provide sufficiently high resolution data to clearly distinguish between these possible contributions to the change in conductivity. From preliminary XRD measurements it appears likely that a secondary phase is appearing, but the nature of this phase is unclear. We expect at high temperatures that a Ruddlesden-Popper phase may form, or a Ba rich phase is exsolved. It is these structural features as a function of temperature and Ba content that will be probed in this work. We will then correlate these data with ex-situ conductivity measurements.