Hello David and welcome to this forum,
Roy served in the famous "Greys" with General French's Cavalry Brigade, his very handsome and pleasing five battle clasp Queens South Africa medal is verified WO100/114 page 155 and his Kings South Africa medal with both clasps is shown on WO100/302 page 385.
All surviving service papers for this period are in WO97, WO363 and WO364, like the original medal rolls mentioned above, they are at The National Archives Kew and most, though not all, are availble on line, so if you can't find them on line, a manual search would be needed to see if they exist, in addition, he is shown on the published (Palmer) casualty roll as Severely Wounded at Groenfontein, moreover, he is shown on the quarterly South African Field Force returns as Missing at Uitval Nek on the 11th July 1900 and later released, this latter also confirms he was Severely wounded on the 30th of December 1901 in the Transvaal at Groenfontein.
Again Welcome David.
Kind regards Frank