Thanks very much for those two suggestions, Janet. I'll add them to the list next time I post a revised version, if they do mail order (do you know if they do - their websites don't seem to mention that?). We've never actually had any Greek nurseries on the list yet, as it's for places that will send out plants at least within their own country (and ideally further afield too). Local MGS branches often have lists of more local recommended suppliers.
Chrysanthi, the lady near Athens that you mention, is apparently still going strong but doesn't do mail order. She's said to be particularly good on Greek native plants. As you say, I'm sure Fleur can give directions.