Shield boss wirh wood and leather remains

Shield boss, height 9.5cm, diam. 17cm. Carinated boss, with stud on top diam. 3.7cm, straight sided or slightly concave dome above very pronounced carination, indented waist, and sloping flange width over 3cm. Flange has remains of 5 disc-head rivets, diam. c. 1.8cm. The boss is badly cracked and damaged, and will fall to pieces very soon. Slight remains of wood and leather on underside. It is slightly 'sandy' looking and could be Gilton perhaps, but not to definite as has egs. Possibly N. Thames eg. Bears slight resemblance to Coll. Antiq. pl. II.1. Ozingell?