Complex sentence: The complex is entered from Grosvenor Road through the Propylaeum, a Grade I listed building consisting of a massive entablature supported on widely-spaced ("areostyle") Doric columns which is flanked by temple-like lodges.
Split into simpler sentences: The complex is entered from Grosvenor Road through the Propylaeum, a Grade I listed building. This consists of a massive entablature supported on widely-spaced ("areostyle") Doric columns, flanked by temple-like lodges.