Given on behalf of the LHCb collaboration: Should the discrepancy between theoretical predictions and measurements of R(D*) and R(D) persist with new data at LHCb and Belle II it will be important to measure lepton non-universality in transitions other than b->c in order to characterise the underlying physics causes. With the large dataset of semi-leptonic decays collected by LHCb in Run 1 and Run 2 even modes that are not CKM favoured are able to be probed. Here a proposal for such a measurement at LHCb with a b->u transition via B->pplnu will be presented. Such an analysis will probe different and complementary physics to the previous R(D) and R(D*) measurements. The steps towards a measurement of R(ppbar) at LHCb will be outlined with the experimental and theoretical challenges highlighted.