The mark you have, Edinburgh Crystal, written in that font, was in use in the early '90s, Roy.
It was on some wineglasses I bought as a wedding present, before I got properly interested in glass.
I was most irritated that the mark was not in the middle of the underside of the foot, but out on the rim, so it showed.
I have just checked the Ionas I also bought in the early '90s. They are marked Edinburgh Scotland. Iona is a hallmark design which is not outsourced. I'm wondering if the use of "crystal" indicates outsourced work.