Complex sentence: An extension opened in 1994, with a frontage onto Church Gate, and another extension (called'Shires West') is under construction which will nearly double the retail space available.
Split into simpler sentences: An extension opened in 1994, with a frontage onto Church Gate. A further extension, known as "Shires West" during the planning and early construction phases, is currently being built, which will nearly double the retail space available.