I am pretty sure there are EU nurseries that sell Duke7 at least, and that should be a very hardy cultivar. I don't know what their minimum orders are, but Viveros Brokaw (in Spain) sells a wide range of Mexican cultivar rootstocks, including Duke7 and Walter Hole seedlings. You would probably need to arrange to have them shipped from Spain yourself, though. Luis hasn't been as active on this forum lately but I'll see if he has a list of EU nurseries that sell hardy avocados, I feel like I've seen him post a few on here or the GF forums.