Complex sentence: Reid and Sigrist was a British engineering company based at Desford, Leicestershire, England, they were an important instrument manufacturer in the interwar era, specialising in aircraft applications mainly producing aircraft parts and instruments but later became a Camera manufacturer.
Split into simpler sentences: Reid and Sigrist was a British engineering company based at Desford, Leicestershire, England. They were an instrument manufacturer in the interwar era, specialising in aircraft applications mainly producing aircraft parts and instruments but later became a Camera manufacturer.