I have come across these 'BRASS' buttons and thought that they were British Army Battledress buttons - but - all British Army Battledress brass buttons were 4 hole not 3 hole as these are.

After searching the only military buttons like these seem to be German issue as the German ones had 3 holes - but - were not brass, or were some? - they are 11/16ths or 17mm.

Anyone have any ideas?

Help identifying these WW1 /WW2 buttons