Complex sentence: The demand for Patties product increased, prompting a series of shops and bakeries to be built, bought and sold until 1985 when a new factory was built and production was moved to Bairnsdale, where it is to this day.
Split into simpler sentences: The demand for Patties' product increased, prompting a series of shops and bakeries to be built, bought and sold. In 1985 a new factory was built and production was moved to Bairnsdale, where it continues to this day.