plant ID help please - perennial cabbage, 'lundy island'?

I know there is a perennial cabbage native to south-west coastal England called Lundy Island cabbage, not sure if this is the same though - found in coastal Wales. The leaves and flowers appear to be bigger than the lundy island I've seen. Anyone know what it is exactly? I've taken some cuttings and am going to try to get it established in my garden. Where I found it, it is THRIVING all over a very exposed site.

http://www.pemcoastphotos.com/_photo_9612185.html

bump - any ideas?

I just want to make sure that it's a nice one to eat really

I really do not know S, just doing some web surfing and there is an edible wild species .

http://en.wikipedia.org/wiki/Brassica_oleracea

http://simple.wikipedia.org/wiki/Brassica_oleracea

http://eol.org/pages/583899/details