Complex sentence: In 1820, a single storey west wing was built by Robert Smirke, and in 1823 Charles Robert Cockerell built an Orangery in the form of another Greek revival temple.
Split into simpler sentences: In 1820, a single storey west wing was designed by architect Robert Smirke. In 1823 Charles Robert Cockerell built an Orangery in the form of a Greek revival temple.