  We present an investigation into the structural and magnetic properties of
Zn-substituted Cu$_{2}$OSeO$_{3}$, a system in which the skyrmion lattice (SkL)
phase in the magnetic field-temperature phase diagram was previously seen to
split as a function of increasing Zn concentration. We find that splitting of
the SkL is only observed in polycrystalline samples and reflects the occurrence
of several coexisting phases with different Zn content, each distinguished by
different magnetic behaviour. No such multiphase behaviour is observed in
single crystal samples.
