In my humble opinion I must say that this rather crumpled piece bares little, if any, similarity to contemporary Anglo Saxon art, although there is a certain likeness concerning shape and material. This site shows a few (later) examples of Anglo Saxon brooches, where the use of a pronounced flange is commonplace:
ads.ahds.ac.uk/catalog...08_018.pdf My favourite piece of Cloisonné work is of course the renowned Alfred Jewel at the Ashmolian Museum:
www.mirror.org/ken.rob...jewel.html