Miss Kitty
Firstly, welcome to the Forum.
I had a quick look on the medal rolls for the 2KSLI (the rolls are titled WO100/194) and on page 388 was located "3464 Pte. S.Ellis"; the Queens South Africa campaign medal issued to that man would bear the clasps "Cape Colony", "Orange Free State" and "Johannesberg". On a later medal roll page (485), that man is shown as also being entitled to the "South Africa 1901" clasp. There is a notation on that entry which reads "Discharged". Please understand that "3464 Pte. S.Ellis" of 2KSLI may not be your GGF. The roll pages do not show a second christian name. Nor is there any entry in the Palmer Casualty Roll for an "S.Ellis" or indeed an "S.E.Ellis" of 2KSLI.
This site often receives queries of this type and sometimes assistance from Forum Members leads to a good result - and sometimes it does not. We are always reliant upon information received to begin with. It is suggested that your next step would be to check one of the commercial sites to see if any personal papers are still extant. That way, any personal details shown may be cross-referenced with what you may already know.
By the way, there is and never was anything the matter with being "only a private"! Armies can't do much without them. And in the Victorian army, forfeiture of pay could have been for quite a number of reasons. Perhaps disciplinary.
Good luck with your quest.
Regards
IL.