Complex sentence: When the plaque was found in the 1930s the Geological Society of London and the Bath Royal Literary and Scientific Institution placed it on the 18th century cottage, although it is now believed that he lived in the nearby Tucking Mill House.
Split into simpler sentences: When the plaque was rediscovered in the 1930s the Geological Society of London and the Bath Royal Literary and Scientific Institution placed it on the 18th century cottage,. However, it is now believed that he actually lived in the nearby Tucking Mill House.