James! You have some nice plants, and we'll look forward to seeing more of your collection.
Thijs, I've been trying to remember and I'm thinking it was a yucca. Is it possibly Yucca nana? I did a quick search and that one came the closest to what I have. It hasn't bloomed for me, so I don't know what the flower stalk looks like. I did look at Agave x leopoldi and it looks very similar to me, so I'm not sure what I have.