I ship in the EU and any other countries that have trade deals that allows plant transfer without requiring phytosanitary certificates (Switzerland for example)! Sadly after Brexit I don't know if I will still be able to ship over the UK :(
Finding the growing space is hard, especially if your plants are big. Thankfully I focus mostly on the Drosera genus, which are mostly small plants. I can fit multiple plants in a 7x7cm pot. I grow the winter-hardy ones in a greenhouse, the tropical ones are grown inside under LEDs.
Finding rare species is not too hard if you have good contacts in the community (I've been part of it for more than 10 years, so it was relatively easy for me). The hard part is propagation. Thankfully for me, a lot of Drosera are really easy to propagate by leaves cuttings but for the species that are not easily propagated, I work with an university that propagate them in tissue culture for me.
Good luck with your project, it requires a lot of work but if you're passionate about it, it won't feel like work!