Complex sentence: It has been proposed that the site of the Old Hall should be excavated to find the remains of the house, however, the site of the original hall was excavated many years ago by the landowner and remains of the hall's foundation stones removed.
Split into simpler sentences: It has been proposed that the site of the Old Hall should be excavated to find the remains of the house. The site of the original hall was excavated, many years ago, by the landowner and remains of the hall's foundation stones removed.