help please anyone

[spatuk]

i have a gs 1200 09 and I'm wanting to fit a rad cover, Ive taken all the screws out that i can see i might have taken more of than i needed, the problem i have is the auxiliary socket on the front left hand side, how do i get to the nut, what size is the nut ,and how do i stop it all spinning when i turn the nut hope this makes sense
regards spatuk paul , new i needed help