Dear Adam!
We don't looking for other marks in your fork, but if your mark is original, you have to see the assay office letter in the mark. For example an A in Wien/Vienna:
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or a C in Prague:
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etc.
Only when we know, where your fork made, can looking for a maker...
Furthermore Amena had a good comment, this curb is very unusual. It's a clear mark?
If you can't tell us more about the marks of the fork, please, make some clearer, sharper image.
Mainly because we know a lot of fake Diana marks...
http://www.925-1000.com/forum/viewtopic ... ana#p90807
Best regards!
Krisztián