Milly, I have had a look at 1st world war uniforms, It seems they all wore woolen jackets with pockets in them, my Grandfathers was the same , he had buttons on the shoulder, pleats above left pocket, which made it 1915/16 and the buttons ? are above the left pocket slightly below the pleat. I haven't seen any with buttons on the tunic, there were loads of them for sale buttons that is.
louisa