Can someone help me to identify and date this please?

I own this set from my grandfathers. It is massive silver (not plated). Thank you very much in advance for any information.

PS: cigarette box on the picture is only as size reference.
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The diamond mark looks like a french makers mark although not been able to identify whose.

If you clean the pentagonal mark with and toothbrush and soap it should be a french fineness mark.