It appears that the medals were never claimed by your grandfather (or next of kin).
The King's Regulations and Orders for the Army 1912.
Section XII Dress, Clothing, Equipment, Medals and Decorations.
2, Medals and Decorations.
General Instructions
1734: "Medals which, at the end of 10 years, still remain unclaimed, will be sent to the India Office (if granted for Indian Service), or to the deputy director of ordnance stores, Royal Dockyard (Medal Branch), Woolwich (if granted for other service) to be broken up."