Complex sentence: Symmonds is the only daughter of Algernon French Symmonds and his wife, Olga "née" Harper and the elder sister of Barbadian diplomat, Algernon Washington Symmonds.
Split into simpler sentences: Symmonds is the only daughter of Algernon French Symmonds and his wife, Olga Harper. She is the elder sister of Barbadian diplomat, Algernon Washington Symmonds.