His KSA (2) is listed on WO100/336p157 with the surname Duerdon. The note attached says the KSA was returned to the Mint 15 June 1910. The remarks on the roll say 'To Army Reserve'. The roll is dated 8 Dec 02.
So did he desert from the Army Reserve? Can you even do that?
I would guess that the KSA was not issued to him as he had, by that time, temporarily left His Majesty's service and that the medal hung around until someone decided to so something about it. Why that took 7 years is another question!