Complex sentence: James Nathan, aged 34, is best known as the winner of the BBC's "Masterchef" 2008, having beaten Emily Ludolf and Jonny Stevenson in the grand final.
Split into simpler sentences: James Nathan, aged 34, is most known for his appearance on "Masterchef" 2008. He was the winner of the program, beating Emily Ludolf and Jonny Stevenson in the grand final.