WW1 being from 1914 to 1918, would mean it was made during the war if the marks was made and dated by the artist, Since they were found in rubble them if the factory was bomb and these were new that would make some sense. However, this was the 1916 would be Art Novea time, these look victorian like mid to late 1800's. I hope our good friend chris will show up, I'm sure he would have the light needed to place the clues and dates in order.
The only other thing I find amazing is they are in wonderful looking condition to have been rubble, and extreamly well cared for I see now grazing and only a little discoloration.