Tinned? copper-alloy buckle and plate

Gatty Slip: 'Anglo-Saxon base silver fibula found at S Lawrence, Isle of Thanet, near Ozengell in Kent. Formerly Rolfe Coll., vide Akerman's Remains of Pagan Saxondom p. 79 pl. 39 fig. 5'Thickly tinned(?) bronze buckle and plate, cast in one piece, total length 14cm. Rectangular loop with flattened upper surface and rounded edges: irregular hole in centre of junction of loop and plate, with traces of iron corrosion - through this was fixed the pin, evidently iron, and perhaps a replacement for an original bronze one. Plate basically triangular: near top are angular projections surmounting semi-circular lobes, and at base twin lobes flanking the central broad convex mid-rib which runs from below rivet hole to bottom of foot. Back of plate rough as left from casting: it shows the sockets, still with iron in them, which were drilled to plug the rivets in place behind the lobes. Rivet holes do not penetrate to front. Just possibly there was a backplate, now missing. The whole appears silvery and looked to be of solid white metal, but in fact there is only a thickish tin(?) plating or tin wash over the whole.Provenance: Ozingelll? St. Lawrence near Ozingell.