The building is flanked to the northwest by a redbrick Belfry topped by a lantern Dome and spire in lead. Inside the Dome, pierced by oval dormer windows, rests on a square base with graceful sprung arches in an arcade over gilded Corinthian capitals. Do not miss seeing the superb retable by Grinling Gibbons in 1686 which occupies the East wall; it is enhanced by delicate wooden sculptures forming floral arabesques.