Can anyone help to identify these marks on a silver ladle?

I am trying to identify what these hallmarks stand for on this soup ladle that I have. I want to try and find out where it might have been made and what sort of date it might have been made?
I have searched on the internet for these but the longer I look the more confused I become. Any help that anyone could offer with this would be much appreciated.
I have taken a photo, attached, but the hallmarks is not very clear I am afraid. There are letters: ‘OW’, mark like ‘+’ or something else, and on other side of spoon are numbers ‘15’ (is it a 15 lothig silver mark???)

Many thanks
Tom F.

I’ve already know the answer.

Those silver hallmarks belongs to Wiskemann from Belgium and Switzerland. The 15 is not for the silver fineness (the ladle is electroplated) but has to do with the thickness of the plating…