I have just been reading about this plant. I do have a sea kale forcer somewhere I can drag out, it was just a prop in a seaside show garden we built once. I can also go foraging along the dunes and see if there are any seedlings later, it will split but I don't want to dig up a mature plant. It is supposed to be like asparagus when it is forced and used like ordinary kale with young leaves. Does anybody grow this stuff for a few tips.