British army postal service Great Britain 2 d orange postage stamps issue King George V. 1912 / 21 on liable to charges (the franchise was at the 25.8.1920 canceled) letter of an Officer the royally artillery (R. A. ) to Pitlochry (Perthshire), ZKr ARMY post OFFICE B 17 OC 21 S. 120 (OS handbook number 2.1.2), covers and postcards of the British Unit in Upper Silesia, the whose field post office S120 mailed were, are very rare, according to OS handbook are up to now only 10 such documents are known, the here offered letter is on this list unlisted, transport traces