Remove w108 hand brake cable from handle inside cabin

[matthewz108]

Hi all,
Just in the process of replacing the hand brake cable that goes from the handle inside the cabin, it through the firewall to the lever down on the passenger side of the radiator.
Question is, how do I release the end of the cable from the handle? There looks to be a grub screw near the end of the handle closest to the firewall that prevents the handle from rotating, which I feel needs to come out to allow the cable to slip out - see blurry part just about an inch up from the cable on the pic below