Complex sentence: In Norman times Wilfrid's abbey was replaced by an Augustinian priory: the church you see today is mainly that building of about 1170-1250, in the Early English style of architecture.
Split into simpler sentences: In Norman times Wilfrid's abbey was replaced by an Augustinian priory. The current church largely dates from that period (c.1170-1250), in the Early English style of architecture.