Complex sentence: There has been a hospital here since at least the start of the second world war, becoming a general hospital post-war, in 2003 a new building was completed establishing it as a community hospital, thus it is more formally known as Herts and Essex Community Hospital.
Split into simpler sentences: There has been a hospital here since at least the outbreak of the Second World War, becoming a general hospital after the war. In 2003 a new building was completed establishing it as a community hospital, thus it is more formally known as Herts and Essex Community Hospital.