The rim of the medal is slightly convex - this also indicates that it is a cast medal & not a die-struck medal

The Distinguished Service Order (DSO) is a military decoration of the United Kingdom

Operational Service Medal Afghanistan

Bars are awarded for each additional period of 720 days

Granted in 1917 and often called the Mons Star it was awarded to all who actually served in France or Belgium on the establishment of a unit between 5th August 1914 and midnight on 22-23 November 1914

OSM Sierra Leone Medal Category_ACSM The rim of the medalOperational Service Sierra Leone. Awarded for service from 2000 in Sierra Leone.