Welsh Mountain ewe urine frequency and volume data measured from tri-axial accelerometers on ewes grazing two upland pastures in North Wales - Marsden, K.A.; Lush, L.; Holmberg, J.A.; Harris, I.M.; Whelan, M.J.; Webb, S.; King, A.J.; Wilson, R.P.; Jones, D.L.; Charteris, A.F.; Cardenas, L.M.; Chadwick, D.R. (NERC Environmental Information Data Centre, 2021)