When I was first shown this object, LEIC-C5F14A, the shape suggested the Viking age, but the decoration didn’t seem to fit. Enamelling and flowers are not what springs to mind on these trefoil mounts, which are usually gilded or plain bronze. Having now managed to loan the object from the finder, I can now confirm that its decoration appears to be thick clumps of niello, with traces of circular depressions in their surface, possibly for silver wire? Along with its surface gilding this would have created a wonderfully shiny object. 
Although the mount is no longer unique, not having enamel as originally thought, it is still very interesting. The form of the terminals are unusual, the heavy use of niello appears to be unusual too and there still aren’t very many complete mounts of this type known.
The trefoil mounts are of continental origin and broadly dateable to the 9th century. It is a moot point whether they were brought into this country in connection with Viking activity, or were imported directly from France and/or the Low Countries.
Either way, this object is stunning and is a valuable addition to the corpus of Early Medieval finds in the county.
