4 letters?

Hi everybody,
I’m new on here and am after a bit of info if anyone can help me.
I’ve been collecting various small silver items for around 10 years or so and like all of you this has become a passion for me.
The item in question that I’m stumped on is a cigarette box that I bought around 8 years ago.
There are what appears to be 4 letter stamps and the maker stamp but no town hallmark ( unless it is worn away ) So I’m a bit confused with this one as to the age and the town it was made in.
There is what could be a worn mark under the ‘made in england’ stamp but as for the 4 letters?
Any help would be greatly appreciated.
Many thanks in advance
Copy of IMG_7676.JPG

Silverplate mark of Roberts & Dore, Sheffield & London, from c.1920.
Letters are EP NS for ElectroPlated Nickel Silver.