Complex sentence: He beat Les Sait over 4 rounds and after 10 more bouts knocked out Laurie Duke for the New South Wales Light Heavyweight Title then won the Australian Light Heavyweight Title beating 6 ft 5 inch Long John McCubbin in Melbourne.
Split into simpler sentences: He beat Les Sait over four rounds, and after ten more bouts knocked out Laurie Duke for the New South Wales Light Heavyweight Title. McNamara then won the Australian Light Heavyweight Title, beating 6 ft, 5 in Long John McCubbin in Melbourne.