Complex sentence: Seahaven is the name given to an area in East Sussex that includes the towns of Seaford and Newhaven and Peacehaven and the surrounding towns in the Ouse Valley which leads to the East Sussex county town of Lewes.
Split into simpler sentences: Seahaven is the name given to an area in East Sussex that includes the towns of Seaford and Newhaven. It also includes Peacehaven and the surrounding towns in the Ouse Valley which leads to the East Sussex county town of Lewes.