I have attempted to add the location of one of Walthamstow's public art works to Open Street Map; the art work being, Shying Horse, at Blackhorse Road Station. As yet the little green dot I can see on the map in my user OSM dashboard is not yet visible on the map in the public domain. The video guide for beginners says it can take quite a while for new information to appear if there is a lot of use of this facility. The dot may well be lost; though I don't imagine a lost dot poster (similar to those for lost pets) would help in it's being found.
Open Street Map can be found here
I last saw the green dot, with a yellow highlight, there (below)
For an existing map of public art in East London, there is Lawrence Rigal's web site, here and a direct link to his information about the artwork, here.
Field Study's Man in E17, boldly losing himself where others have lost themselves before.