Hi Richard im new to this forum but i think you have posted in the wrong section try posting in the middle east section.
as for the mark im very familiar with most persian silver hallmarks but i have never seen this hallmark before. persian silver is usually marked 84 either in english or generally in farsi the eight looks like a upside down V some have the makers mark as well and some do not. generally speaking the fine pieces do. this looks to me like a mark that was maybe added after this piece was either imported or made. hope this helped and good luck.