Complex sentence: Since his ancestor John Pawson preached with John Wesley in the 18th century, the Pawsons have been farmers, (Methodist) preachers or both, and his father, Professor Cecil Pawson, was involved with both.
Split into simpler sentences: Since his ancestor John Pawson preached with John Wesley in the 18th century, the Pawsons have been farmers, (Methodist) preachers or both. His father, Professor Cecil Pawson, was involved with both.