Complex sentence: The largest and best known of these local coach-builders was Holden's Motor Body Builders, and in the mid- 1920s Holden commenced importing standard production Austin Seven rolling chassis and building Australian-bodied Austin Seven tourer and roadster models.
Split into simpler sentences: The largest and best known of these companies was Holden's Motor Body Builders. Holden was already manufacturing bodies for other marques, and in the mid- 1920s commenced importing Austin Seven rolling chassis and building Australian-bodied Austin Seven tourer and roadster models.