There were two of these clips in the pack from ebay. The clip worked, sort of. But not real happy with the setup. https://www.ebay.com.au/itm/295229103746
Some photos of the clip in position. (Server error when uploading. I hope they got there.) The blue and red arrows show the poor fit, highlighting the gap between the link arms. That's the gap between the ball and the other link arm. The problem is that the gap between the neck and the link arm is greater, but you can't see that in the photo. The other two pics show the short piece of garden hose in place. That's a piece of the hose at the side.
It was fiddly to fit, being made of spring steel. I hope it's stainless steel. The side of the clip with the narrow slot is underneath the ball. You can't see that in the photo. The other side of the clip fits over the other arm, locks in place, and keeps them together. When fitted it was clear that the clip wasn't going to fall off, which was my concern.
I had hoped the clip would have pulled the ball snug against the clip and taken up the slack. It doesn't. All the clip does is to keep the two link arms together. The trouble with that is that without the original plastic bush in place there's a large gap between the ball on one link and the hole on the other. The pic with the blue and red arrows shows the gap, but it's larger than that because the link wants to run below the ball, at the narrowest part, in the neck. I'd estimate there to have been about a quarter inch free movement in each direction. If you were to fit it to the car like that the slack may have resulted in a noisy wiper mechanism and in moving across the screen the blades would stop before moving back, then stop again before the return wipe. They wouldn't be smooth. The movement may have damaged the clip.
Dirty solution: I cut off a piece of half-inch garden hose (maybe three-eight's of an inch in length) and squeezed it over the ball. (Heavy duty hose I happened to have.) It was a tight fit. Hot water helped. And getting the other link over the hose was also a tight fit. The hose can't be allowed go all the way to the bottom otherwise the clip won't go on. Fiddly.
So, the garden hose became the new bush to stop the slack, and the clip simply held the two links in place.
I didn't apply any lubricant. Not sure if that was a good idea or not. I didn't know what grease would do to the hose, and being exposed I didn't want dust sticking to the grease and wearing out the hose.
The hose being a firm fit everywhere meant there was some resistance, more than I'd like, but it wasn't too bad. The wipers operate smoothly. I'll know when the hose is wearing when the wipers start to clunk on each sweep.
It's worthwhile trying to push some grease into the other bushes. The one I had to disconnect to get the links into place had no grease and the ball was rusty.
If this fails I'll try for the ball joint solution.