Complex sentence: The Banner Lane factory continued to supply kits to foreign manufacturers until 24 December 2002, and when production ceased, 3,307,996 tractor or kits had been built at the factory.
Split into simpler sentences: The Banner Lane factory continued to supply kits to foreign manufacturers until 24 December 2002. By the time production ceased, 3,307,996 tractor or kits had been built at the factory.