It probably has: I have vague recollections of something similar. I thought, give the restrictions imposed by the theme, this was a very clever piece of construction. I left the 28ac 'til last, as It was fairly easy to see what was going on, but I still needed a second printed grid having started (sorry, Ragtag) in my lucky ballpoint. Also initially missed some of the added letters,as I felt there were one or two which were kind of optional. However, a very pretty début (if such it is) and thanks