From what I remember, Tristan went to huge lengths to legally import Mexicola seed then grew them out and sold most of them. I had two of them but they're not old enough to fruit yet.
I have no idea if he imported more seed. If he did the seedlings will still be expensive and in limited supply. If not the supply will be super short until the young trees are old enough to bear fruit. Then the price ahould plummet as Europe becomes home to ever greater supplies of frost hardy avocado trees.