I had the engine out and decided to look into a fix for the problem. I'm not sure what caused the joint to get sloppy but the problem was that the plastic bushes that did the driving were not in direct contact with the drive flanges so the drive had to go through the rubber joint which was where the movement was. The picture below shows the plastic bushes not in contact with the steel drive flanges.
To try and fix this problem I machined up steel replacements for the plastic bushes that were a better fit. 20mm od, 12.5mm id and the same length as the plastic ones. This seems to have fixed the problem of the sloppy steering.
