Elite Lensman
Newbie

Hi, I am researching my family tree and have just obtained my grandfathers RN service record from the national archives and was hoping someone may be able to help answer some questions about it. He served between 1929 and 1952.
Firstly, it lists as his "Trade or Occupation" as "Messenger" can anyone explain exactly what a messenger was and what they did ?.
Secondly, listed on the right are "Badges G. D. or R." see below,

can anyone explain the meaning of the letters in the G. D. or R. column.
Thanks
Firstly, it lists as his "Trade or Occupation" as "Messenger" can anyone explain exactly what a messenger was and what they did ?.
Secondly, listed on the right are "Badges G. D. or R." see below,

can anyone explain the meaning of the letters in the G. D. or R. column.
Thanks