Very interesting looking individual. It doesn't actually look like any of the other dik-dik species in other ways but they seem to be silvery like this. Silver dik-dik most obviously.
I agree - it looks like there might be two different species of dik-diks. I don't know this group very well, but the individual on the left looks like photos that I've seen of Salt's Dik-dik (Madoqua saltiana) while the one on the right looks like a typical Kirk's Dik-dik. But Silver Dik-dik (Madoqua piacentinii) is also a possibility. It's very likely that Salt's Dik-dik and Silver Dik-dik are subspecies of the same species or are sister species. There used to be some Salt's Dik-diks in captivity in the U.S. (back in the 1980s) but I don't know about their status in the recent past in Europe.
It might be a silver-coloured dikdik, but it is not a silver dikdik, which haven't been in Western Europe for a long time. The prominent white eye ring and size (silver dikdik are smaller than Kirk's) are give-aways. To me it looks like a Kirk's dikdik with a quite unique pelage.
