Complex sentence: There is no known record of a church in Headley at this period as the first records of a church are after the Norman Conquest however this church could have been build on or adjacent to a Saxon church.
Split into simpler sentences: There is no known record of a church in Headley during this period; the first records of a church are after the Norman Conquest. However this church could have been built on or adjacent to the site of a Saxon church.