Some time ago, Abyaneh and Fleischmann submitted several papers to this journal in which they modelled the heterogeneous nucleation of crystals as a first order kinetic process. In an invited response, I argued that such an approach was seriously flawed, because it ignored nucleation rate dispersion. More recently, instead of responding directly to this criticism, Abyaneh and Fleischmann have challenged the validity of the Deutscher-Fletcher experiments that first established the physical reality of nucleation rate dispersion. This note, therefore, serves two purposes. Firstly, it confirms the validity and high rigour of the original Deutscher-Fletcher experiments. Secondly, it identifies the errors in the Abyaneh-Fleischmann papers. In conclusion, it is emphasised that nucleation rate dispersion is real, universal, and must always be taken into account in experiments involving heterogeneous nucleation.