Complex sentence: Pulford Castle, which no longer exsts, only the mound of the castle remains just behind the church of S Mary, was a small Norman motte-and-bailey defensive structure, exists on the outskirts of the village.
Split into simpler sentences: Pulford Castle, which no longer stands, was a small Norman motte-and-bailey defensive structure. Today, only the mound of the castle remains, just behind the church of S Mary, on the outskirts of the village.