I don’t think so because the bolt through the tiller arm (and also the steering gear box output arm) also goes through the ends of the steering drag arm which connects the gearbox to the tiller. I am thinking that the problem might possibly be in the joints at the end of the drag link arm and these are replaceable.

Or I might have to fit a longer bolt so I can positively clamp the bolt to the tiller arm and then an extra nut clamping the drag arm end to the bolt – this might avoid replacing the tiller arm. I will have to see what I can see when I take the boat out the water for annual maintenance.