Thermalisation of single electron devices is of considerable current interest because of its fundamental and practical consequences. We present experimental evidence of the effect of electrode volume and its shape on thermal equilibration of small metallic islands for single electron tunnelling. Heat transport between the conduction electrons and the lattice in a metal is commonly accepted to obey the ∞ Te5 - T05 law at low electron and lattice temperatures, Te and To, respectively. We have investigated the power law and found that it obeys the ∞ T5 law only for the smallest islands, and in the majority of the cases considered, it rather follows a law ∞ TP, where p <5. The thermal coupling can be improved by increasing the volume of the island, but, upon increasing the surface area alone, the effective coupling constant is reduced indicating the presence of local hot electrons.