Interesting fact to come out of the new book by the Queen's dresser;
"The dressmaker reveals that the Queen was “very specific” about the evening gown she wanted to wear for a state banquet in Dublin in May last year, which featured more than 2,000 silk shamrocks especially designed and sewn on by hand as well as an Irish harp design made of crystals."
So the Irish Harp design on that gown was not a brooch, but an applique. Problem solved!