Why is the stamp so old yet the box made later on in 20th ? The box on the inside is plain same pattern as outside except underneath lid is a fancy swirl design
It can happen. Also, the whole mark might be registered to the company that designed the case / box
There was a company called Levi & Salaman who were founded in 1870. They became well known as very fine silversmiths, particularly rare pin cushions etc. but perhaps they designed the case / box during the early years of the company - they initially made items from gilt or base metals.
It's possible and worth pursuing to a degree because the case / box will be worth more if it was designed by Levi and Salaman. That registered design will be available from the National Archives in Kew Gardens, i think. The I on the top is a roman numeral which relates to the Group of items that design was allocated. Group I is metalware.
The National Archives link is below and you might need reference BT 45 to BT 49.
http://discovery.nationalarchives.gov.uk/SearchUI/browse/C3086?v=r