Hi VanZyl, welcome aboard.
No. 1514, Tpr Gerald Schoon (name appears as Gerald on the roll), Johannesburg Mounted Rifles is shown on the Queen's South Africa Medal (QSA WO 100/253 pg 126, JHB 30 July 1902) roll as having been awarded medal plus Cape Colony, Orange Free state, & Transvaal clasps. Under remarks is entered "Q'land Mtd Inf" the land has been crossed out and "town" entered above it. This would indicate he had previous service in the Queenstown Mounted Infantry.
On Army Order No.233 of 1 October 1902 (QSA WO 100/253 pg 227, JMR, Cape Town, 21 Sept 1904) it shows the awarding of a South Africa 1901 clasp to him. His name is again given as Gerald. Service is entered as 24-6-00 to 21-6-01. Under the column for service in other units is written "No" but this has been crossed out and "Q'land Mtd Inf" has been entered above but "land" isn't crossed out this time. I presume the former correction of Queenstown Mounted Infantry is correct.
With Scoon having served first with an Eastern Cape unit I noticed that there was a C. Schoon in the Prince Alfred's Guards Mounted Infantry and a W. Schoon in the Midland Mounted Rifles, both Cape units.
Attestation papers for the QMI are held by The National Archives (UK) in series WO126 boxes 145-163.
Cheers,
Mark