Complex sentence: He tried his new product on his nieces and nephews until he had it perfected, and in 1928 he registered the tradename "Weetbix" and production started at 659 Parramatta Road, Leichhardt, NSW with the financial backing of Arthur Shannon.
Split into simpler sentences: He tried his new product on his nieces and nephews until he had it perfected, and in 1928 registered the tradename "Weetbix". Production began at 659 Parramatta Road, Leichhardt with the financial backing of Arthur Shannon.