By the way, the sign at the northern end is the little round sign in this Mapillary image, on a pole that's set in the brickwork for that walkway. It's 90% faded as mentioned in other changeset comments.

https://www.mapillary.com/app/?lat=51.5139713&lng=0.0027414&z=17&pKey=6051898158155110&focus=photo&x=0.3394868821773948&y=0.38727828005875437&zoom=1.6796769851951558