Complex sentence: It was designed by Vincent Harris OBE (1876--1971) and Thomas Anderson Moodie (1874--1948), who won the design competition for the building in 1909, the project was completed in 1911 and the building was opened in 1912.
Split into simpler sentences: It was designed by Vincent Harris OBE (1876--1971) and Thomas Anderson Moodie (1874--1948), who won the design competition for the building in 1909. The project was completed in 1911 and the building was opened in 1912.