Complex sentence: The company also opened superstores in Great Britain during the 1980s, the first of which opened in 1986 in Billingham on Leeholme Road and sold both groceries and non-food until 1996 when the store closed its grocery department.
Split into simpler sentences: The company also opened superstores in Great Britain during the 1980s. The first British store opened in 1986 in Billingham on Leeholme Road and sold both groceries and non-food until 1996 when the store closed its grocery department.