^ I'll follow up the fat lush
and agree on the National Gallery. Also located steps away at Trafalgar Square is the St Martin in the Fields church. Smaller than Westminster and my kids enjoyed the brass rubbing there...
Edit: Love the Fullers as well. Stick to the local beers when in the pubs though lately I've lot's of Bud and Coor's Light which seems to sell surprisingly well with the locals.