Complex sentence: The established distilling business of Fox & Williamson began the distilling of Plymouth Gin in 1793: soon the business was to become known as Coates & Co. which it remained until March 2004.
Split into simpler sentences: The established distilling business of Fox & Williamson began the distilling of the Plymouth brand in 1793. Soon, the business was to become known as Coates & Co., which it remained until March 2004.