I have spotted a slight bit of corrosion on the brake disk mount, so I need to remove the mount and rear axle? Do I need to remove the nut on the socket and remove that side to get the other side off? So do I need to remove all of this? Is it possible to just remove this side, if so, how?
The disc mount is part of the hub so the hole assembly needs to be taken apart, that includes the sprocket assembly side. Be careful to note how it all comes apart tho as there maybe shims there.
Undo the nut on the chain/sprocket side and you should be able to pull the axle, to which the brake rotor mount is fixed, through from the RHS. Note you may need to drift it out, depending how mucky it is inside. While it’s apart it’s a good idea to disassemble the eccentric adjuster, clean out all the accumulated road dirt, grease thoroughly and reassemble.