Thank you for your reply, but as a total newbie I have no idea what you mean or how to go about to «use the hallmarks..»
Gold and silver cases have a tiny stamp that gives an indication of year and origin. http://www.vintagewatchstraps.com/britishhallmarkexamples.php
The Swiss standard mark for a .800 silver case is a grouse. The presence of a grouse stamp tells me the case was made in Switzerland. Did the Swiss have a system for marking the age of a case? The photos aren’t really clear enough to be able to decipher the other punch marks.
The large stamp above the 0.800 looks like the German Crown and Crescent assay mark. The crown & crescent moon are used in conjunction with a maker's mark and a decimal silver standard mark. (link)
I will try to take some better photos with more detail as soon as I get a hold of a proper camera. Hopefully this will help you guys