The mark you need to look at is the date hallmark in the inset picture above 3103. Note, those are marks from the Birmingham assay office, the letter mark, third to the right is the date mark. From your picture, it looks like an X in the style of the mark used in 1997. Full series of Birmingham marks can be seen here,
http://www.silvercollection.it/englishsilverhallmarksBIR.html
Dave