Complex sentence: Thomas "Tom" Clarkson was an English professional rugby league footballer who played in the 1920s, playing at representative level for England, and at club level for Leigh, as a, i.e. number 1.
Split into simpler sentences: Thomas "Tom" Clarkson was an English professional rugby league footballer who played in the 1920s. He played at representative level for England, and at club level for Leigh, as a, i.e. number 1.