Great Britain 1929 ½d-1½d Postal Union Congress, SG434/6aGreat Britain 1929 d 1d Postal Union Congress. (Watermark Sideways), SG434 6a. Very fine unmounted mint, with full original gum, set of three. Issued to mark the meeting of the Universal Postal Union in London on 10 May 1929. The selected designs were due to be submitted to King George V for his approval, however, the Kings illness at the end of 1928 prevented this, so Queen Mary approved them. Scarce in unmounted mint condition with the watermark