Those Antarctic islands are the Balleny Islands. I took a cruise a couple of years ago from NZ to Antarctica, and we were able to land on Borradaile island [1], one of the Ballenys. I can't find my notes for the exact figure, but the historian on board said that, including us, only a few hundred people had ever set foot there. Many expeditions pass within sight of them, but landing is treacherous--IIRC, we went onshore for about an hour in the morning, and by lunch it no longer would've been possible to do so.
Yes! Balleny! That is a really great story, I'm jealous you got to go there. That aligns with my understanding that it's very difficult to actually land there even if you plan it really well. Sounds like you had the luck of a lifetime, amazing.
[1] https://en.wikipedia.org/wiki/Borradaile_Island