Complex sentence: Since the late 19th century, fairgrounds in the UK have been run the Showmen's Guild of Great Britain which lays down rules for managing and running fairs, helps organize fairs and settle member disputes and serves to protect members from deleterious legislation.
Split into simpler sentences: Since the late 19th century, fairgrounds in the UK have been run the Showmen's Guild of Great Britain. This lays down rules for managing and running fairs, helps them organize fairs and settle member disputes and serves to protect them from deleterious legislation.