Hi,
To me, these appear to be English platers' marks.
They bear similarities to this sequence of marks, often found with a variety of accompanying initials:
It may be that of a manufacturer of blanks who was supplying silver platers and marked the pieces with their initials.
The below is the mark of Thomas Wilkinson, the fourth mark being his famous Pelican device. His former manufactory, the Pelican Works, is a well known landmark at Birmingham. Thomas Wilkinson was in business from 1832 until 1932.
Trev.