Complex sentence: Former employers in the town were the Central Electricity Generating Board (CEGB), the Milk Marketing Board and ICI who occupied offices and laboratories at Hornbeam Park where Crimplene was invented in the 1950s and named after the nearby Crimple Valley and beck.
Split into simpler sentences: Former employers in the town were ICI, who occupied offices and laboratories at Hornbeam Park, the Central Electricity Generating Board (CEGB), and the Milk Marketing Board. ICI's laboratories at Hornbeam Park were where Crimplene was invented in the 1950s, named after the nearby Crimple Valley and Beck.