Presentations of some of the possibilities of observing cation and anion order in perosvkite based structures in order to solve their structure or to solve other questions, when they could not be solved by bulk diffraction techniques. The examples include a (Pb,Bi)FeO3-d compound, a solid oxide fuel cell compound Sr(Nb,Co,Fe)O3-d and several brownmillerite related compounds, as well as a "relaxor ferromagnetic". This was an invited lecture given at the Spring meeting of the British Crystallographic Association in 2014.