Complex sentence: Slapton once had a splendid 18th century rectory of classical design, this was demolished in the 1960s and a development of terraced houses in the style of that era was built on its site.
Split into simpler sentences: Slapton once had a splendid 18th century rectory of classical design. This was demolished in the 1960s and a development of terraced houses in the style of that era was built on its site.