Complex sentence: Either way, she was surpassed by Louisa Thiers in 1925, but she is still the only ever supercentenarian from the Channel Islands and one of the few recorded persons who lived in the 18th, 19th and 20th centuries.
Split into simpler sentences: Either way, she was surpassed by Louisa Thiers in 1925. She is one of the few recorded persons who lived in the 18th, 19th and 20th centuries.