I am just trying to find out more about my great grandfather and his involvement in the first world war. Thanks.
That would be for the 21st London Regiment (1st Surrey Rifles). WWI medals should be issued with the soldiers serial number, rank name and regiment stamped on the back or rim.
The majority of WWI service records were destroyed in a fire during WWII.. However you can check the records at the National Archives which is often free round about Nov 11th to see if they exist.