TOPIC:

I have official correspondence (dated circa 1978) that reflect my Grandfathers entitlement to both the Boer War medals.
However it has never been issued to him or his descendants. What has happened to the MoD Department that originally
were responsible for the issue of medals ? It is noted that the last medal issued was in 1975.

What has happened to the un-issued stock, and has everything been nullified with Independance ?

I don't believe the status of South Africa as a country would impact this - the soldier fought there, and sovereignty would not change eligibility. A search suggests that the MOD will still produce medals for campaigns up to and including the First World War, the caveat being the originals must have been officially returned or, I assume, never issued. Current guidance in the form states that medal requests on behalf of a deceased servicemember can be made by the closest kin, of which one of the options is eldest grandchild. You might as such fit from this angle, but whether a set of medals as old as this has simply 'timed out' is beyond me.