Complex sentence: Later in life, he became a British citizen, settling in Brighton, and represented its government, having a colourful career as a diplomat, including helping to free British diplomats from captivity in Etheopia.
Split into simpler sentences: Later in life, he emigrated to the British, where he was naturalized as a British citizen, settling in Brighton. He represented the government as a diplomat, helping to free British diplomats from captivity in Etheopia.