Any suggestions on this item?

Christophle marked silver plate pot 5 inches high Probably for coffee. The stamp on the base has 1 & 5 in it. I am told by my mother in law that it was taken as booty by her father, a WW2 Royal Navy officer, from a German U- boat that was captured, though maybe it could have been surrendered at the end of the war.

There is a distinctive Anchor symbol with two letter Cs inside, possible standing for Christophle or it could be some German navy symbol.