This is an unrecorded mark used by the partnership of Samuel Goodbehere, Edward Wigan And James Bult.
It is similar to their often seen mark, but there are an additional two pellets at the base. It's presumably an indicator of something, but of what, I have no idea.
I have only seen this mark twice and they were both on 1804 teaspoons.
Below is a couple of examples of their usual mark, often seen overstamping the mark of another.