Complex sentence: She lived in Sussex during the 1950's and 60's for about fifteen years and around 1975 moved to Oxford after which no more is known. She returned to London and died in Fulham May 1987.
Split into simpler sentences: She lived in Sussex during the 1950's and 1960's for about fifteen years and around 1975 moved to Oxford after which no more is known. However, she appears to have returned to London and died in Fulham May 1987.