The addition of RF heating to an NBI-driven target discharge is observed to reduce the toroidal rotation frequency. Experiments on this effect were performed on JET using (H)-D and (3He)-D minority ICRH to vary the bulk electron to ion heating ratio. However, to lowest order, there is no clear difference in the two heating scenarios. We apply a recent model of Nishijima et al. based upon the degradation of confinement with auxiliary power, and find that these JET data are in reasonable agreement with it.