Question about a building on the Thames River.

Hi all, Mom and I took a cruise on the Thames River yesterday. One of the buildings we passed had a white circle at the top with a black letter E.
I don’t think I can post the picture on here, but looking back through my pictures later I can’t remember why the tour guide said this building was important. I tried googling it, but I’m not coming up with anything. I know it’s a long shot without being able to see the photo, but can anyone help? It’s a brick building with a triangular shaped roof and the white circle with a capital letter E is in the middle of the triangular shaped roof. There are several red balconies in a line down the center of the building and a white fence surrounding the building. It looks to be about four stories tall and the building directly behind it has the word warehouse written across the top. Thanks in advance if anyone can help me solve this mystery so that I know why I took this picture! I need to write these things down.😝