I see from the ad below this box that Unwin's sell Eryngium seeds.

If you google it you'll find quite a few suppliers selling seeds and some nurseries selling plants. And there are two seed sellers on ebay as well.

thanks alot beattie will try have looked but seems its the only one not for sale as plant could try seeds thanks again

There are numerous nurseries selling it, i ordered some 2 weeks ago.
Look at the nurseries i mentioned in a blog i wrote some time ago, at least 2 nurseries on that list sell it.

It is sometimes for sale as a plant, Malrky, but it is difficult to grow to a decent, saleable, size in a pot. Eryngium have heavy tap roots which don't like to be damaged, hence the difficulty in repotting and planting out; don't even think of moving one in the garden!
Seed is the best option and then plant it out early in its required flowering position.