Complex sentence: He left Archbishop Michael Ramsey School in Camberwell at 13 years of age with no qualifications to pursue a promising career in boxing and three years later in 1989 He won the Junior ABA National Boxing Title.
Split into simpler sentences: He left Archbishop Michael Ramsey School in Camberwell at 13 years of age with no qualifications to pursue a promising career in boxing. Three years later in 1989 he won the Junior ABA National Boxing Title.