Robert, Welcome to the Forum.
As you are researching your family history are you a paid up subscriber to Ancestry & Find My Past?
If Ancestry choose the Military Search option and enter R (not Robert) Whybourne as his name and 7929 in the Keyword Box - he should come out as the top two selections listed on medal rolls for the 3rd Battalion Royal Sussex Regiment - he earned the Queen's South Africa Medal with 5 clasps - Cape Colony, Orange Free State, Transvaal, South Africa 1901 & South Africa 1902.
If Find My Past again do a Military Search and enter his name as Robert Whybourne and enter 7929 in the Soldier Number box and you will find his attestation papers & service records (4 pages in total).
Follow this link to find out the contribution the 3rd Battalion made to the South African (Boer) War of 1899-1902:
www.angloboerwar.com/books/129-du-moulin...-the-third-battalion
Regards, David.
PS if you don't belong to Ancestry or FMP scream "Help".