I was coming to the conclusion that this wasn't right, as the photo in Craig of caerula does show wool, and this plant seems ot have none to speak of. So, whether the plant was wrongly named, or whether the seed wasn't true, who knows now, and though its a rather flatter form that some of my other formosas, I think it has to be basic, simple formosa ssp formosa. For a while I did wonder whether it might not be a formosa at all, because of its flattened shape, but that it might be a heyderi ssp. gummifera, but I'm now thinking it is closer to formosa, mainly because the spination is much tighter than on gummifera, and the rate of growth much slower.
But I could be wrong, and would welcome other views.