I have managed to find, on familysearch, a baptism for a child born to James Shelton and Elizabeth Catherine ? - James ErnestShelton b 12/9/1903. He was baptised at St. Alban the Martyr Pretoria, and they lived in Klipriver. James Snr was a mason.
There is another baptism for a John Gerald Brabaut Shelton 15/3/1900 in Aliwal North - born to James and Kate Shelton. This James was also a mason.
Not sure if these are of any help, but your Shelton's are not easy to find!