Thank you for this IL. It does help to explain why so many medals to units raised for the war, particularly in South Africa such as are listed in the advert, are marked as returned on the medal rolls.
The authorities made up the medal and then waited for recipients who survived the war to make an application. These units only existed during the war so when it came to issue medals in the years afterwards this was a practical way to contact past unit members. I can only think of TMI which has dedicated records of addresses but most of the attestation papers do have some form of address, albeit that some addresses are 'care of' the Post Office in, for example, Cape Town and others, who filled out multiple attestation papers, sometimes gave different addresses.
It does seem that an attempt was made to issue medals to the next of kin to those who did not survive the war.
Those who did not see the advertisement for whatever reason were disadvantaged. The authorities held the medals for a few years (until 1907-1909) and then returned any unclaimed to Woolwich, presumably to be melted back down.