cover Undated XU5 to Switzerland showing fine boxed "FREE/FROM/PRISONER/OF WAR." in black (POW-1) with circular "POST FREE/P.C./PRISONER OF WAR" (POW-4b) alongside; also 1919 (26 Apr.) XU5 to England, franked at 1d. and showing faint circular "FROM PRISONER OF WAR/PC/(A)/MALTA/FREE" (POW-3) and a OHMS front with circular "FROM PRISONER OF WAR/PC/MALTA./FREE" (POW-2b) in violet. Photo