Current guidance given on plate bearing testing of granular soils suggests that the plate be at least five times the nominal size of the coarsest material. However this limiting ratio can have a huge influence on the reaction load required from plant and resources when conducted to confirm strength parameters used in the design of the sub grade and platform materials of working piling platforms. The aim of the research presented in this paper was to investigate the effect of particle to plate size to establish, if any correlation which would allow the use of a smaller plate size and plant on site to allow more economical plate testing of the platform for design purposes. Different sized model plate bearing tests were carried out in a centrifuge on a large, coarse grained Devonian Limestone. The results from the test series reported show a good similarity in the bearing stress against displacement behaviour between the different sized plate sizes.