The intrinsically low lattice thermal conductivities found for the tetrahedrites Cu12+x(Ni,Zn)ySb4S13 result in promising thermoelectric performances at elevated temperatures. We wish to explore whether such low thermal conductivities are related to increasing levels of copper disorder with increasing temperature. We also wish to explore the effect of copper excess on the degree of copper disorder. We will seek to collect powder neutron diffraction data over the temperature range 300<T/K<700 to investigate the evolution of the crystal structure, the anisotropic thermal parameters of the copper atoms and the occupancies of the metal sites as a function of temperature. We will also aim to exploit the contrast between neighbouring elements afforded by neutron diffraction to establish the transition metal distribution between tetrahedral and trigonal planar sites in these phases.