Not only that, but a tile kiln has also been found. The site is at St Martin-in-the-Fields in Trafalgar Square, and also has a late Roman burial (4th-5th century) and 7th century Anglo-Saxon burials too. The full report, from The Times of 1st December can be found here.
Here are the tile-related sentences:
' ... Other finds include a Roman tile kiln, dating from AD400-450, indicating that a significant Roman building existed near the site ...'
' ... No other tile kilns have been found in Central London, and the kiln is the latest-dated structure from Roman London to have been found thus far ...'
Hopefully, we'll hear much more about this in the future.