While the temperature dependence of the z-axis polarisation is in great agreement with experiment, the xy-plane polarisation is not reproduced as well with the current model. Instead, it resembles phases observed in the related TMCMCdBr 3 , and the TMCM 1-x TMFM x CdCl 3 and TMCMCdBrCl 2 solid solutions. This shows that a close competition between strain stabilised long-range order and entropic stabilisation is present in this structural family.