Castle Garth, coffin paten

During excavations by NEEC a bronze coffin paten (shallow dish) was found. It measured just over 5 inches in diameter. The central part was sunken with the Holy Lamb rudely engraved. Diagonally across the left shoulder was a Latin cross with stepped base. Around the rim was a roughly cut inscription: AHNVSDIPVITOLISPCATAMVNDIMIS. If spelt correctly it should say "O Lamb of God: that takest away the sins of the world; have mercy upon us". Late 12th century or early 13th century.