Complex sentence: The company continued operating into the 20th century, but suffered a setback during World War II, when the Blitz destroyed its Duke Street offices; after the war, the firm decided to concentrate on expanding its presses in Beccles.
Split into simpler sentences: The company continued operating into the 20th century, but suffered a setback during World War II, when the Blitz destroyed its Duke Street offices. Folloiwng the war, the firm decided to concentrate on expanding its presses in Beccles.