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Those are from Elkington & Co. of Birmingham, England, but they're silver plate, not silver. The date code 'X' in a diamond lozenge is for 1862.
Unfortunately, despite being Victorian in age, their antiquity doesn't give them much additional value. You haven't shown them out of the canteen case, and their actual value will be determined by what the utensils are and the desirability of the pattern. From what I can see, there are only spoons and forks in two sizes, not full place settings. As such they would only attract a buyer who wants to add to a set they already have and so a popular pattern would make them more saleable.
I would expect them to fetch in the region $100-$200