Hi Tim - thanks for looking. Not sure if they rearranged the page after you'd seen it. It does look like 5th piece 4th row, but it isn't an iridised piece. Unfortunately, a number of makers seem to have used the same design and I don't know what the differences would be.........size maybe?
I'm not planning on keeping this particular item and I don't want to mis-describe it. Maybe we'll get a definitive answer one day, then again maybe these are items that can't ever be really attributed 100% to one maker. I don't know - But the site was very useful and has been added to the growing list!