I was wondering if somebody knew whether the hallmark 84 in a square frame plus J. & W. Tubben means that the spoons in question are Russian 800 or French plate or something entirely different. I am new to this forum, so I hope the link to the picture works!
French plate is often confused with Russian ``84`` hallmark. The number indicates the thickness of silver plating in microns — you can find several different numbers in one cutlery set (thicker silver plating where more wear is expected — e.g. spoons, lower number in items with less wear expected — cake and sugar thongs).