Complex sentence: The Challenger was built by Royal Ordnance Factories (ROF), in 1986 ROF Leeds (and the Challenger production line) were acquired by Vickers Defence Systems (later Alvis Vickers).
Split into simpler sentences: The Challenger was built by the Royal Ordnance Factories (ROF). In 1986 ROF Leeds (and the Challenger production line) were acquired by Vickers Defence Systems (later Alvis Vickers).