Vintage silver celtic knotwork brooch

Thispretty brooch features cetlic knotwork and the silver is quite thick. It has a safety style clasp and is marked 925 the back and SGO ( presumably the maker).. It is 2” long by 0.5” deep and condition is very good .More illustrations can be provided and I am happy to combine postage on all my items . Please note jewellery is only covered for loss by royal mail if sent special delivery.