Complex sentence: Pendragon became a public limited company when the vehicle division of Williams PLC was de-merged in 1989, operating 19 car dealerships, representing specialist and luxury franchises, as well as a small contract hire business.
Split into simpler sentences: Pendragon became a public limited company, when the vehicle division of Williams PLC was demerged in 1989, which operating 19 car dealerships, representing specialist and luxury franchises. This was as well as a small contract hire business.