Complex sentence: During the Second World War the hall and part of the park became the headquarters for the Royal Engineers Survey, a specialist branch of the RE responsible for providing training for sappers who staffed the mobile Map Production units which were part of all British Army operations.
Split into simpler sentences: During the Second World War the hall and part of the park became the headquarters for the Royal Engineers Survey. A specialist branch of the RE responsible for providing training for sappers who staffed the mobile Map Production units which were part of all British Army operations.