I think they are sometimes called Italian broccoli actually. I haven't seen the purple ones before. I've seen purple cauliflower though which I imagine is very similar.
We haven't been to Greece yet so I haven't seen the markets there. You'll have to take photos and do a post when you go so I can see them.
unless these devices advance enough you can text message me a couple pounds
Reminds me of Willy Wonka and the Chocolate Factory lol