Complex sentence: Though the United Kingdom often set the precedence for postage stamps and their designs, they were the late runners with the issue of their first commemorative stamp, not issuing one until 1924 when it printed and released the British Empire Exhibition issue of 1924.
Split into simpler sentences: Though the United Kingdom often set the precedence for postage stamps and their designs, they were the late runners with the issue of their first commemorative stamp, not issuing one until 1924. The United Kingdom, though credited for the first postage stamp, did not issue a commemorative stamp until 1924 when it printed and released the British Empire Exhibition issue of 1924.