RM records help

Hi

I have my great grandfathers RM record and would like a bit of help trying to decipher some of it if possible please. He served from 1925-1946. My grandmother is still alive aged 95 so I would like to tell her as much about her father as possible. I am ex military so can understand a lot but not bits relevant to RM. Anyone out there that may be willing and able to assist me please?