I've uploaded some of my photos, having just put the rudder back in:
https://imgur.com/a/qJpSkWhat happened is that the housing corroded (pitting) and that and some fouling and calcification caused the bearing to seize inside the housing, making it no longer self-aligning. That probably caused it to wear faster, plus normal wear over 15 years. In the end the rudder turned easily, but had some movement (perhaps half a millimeter) in the bottom bearing. I had to chisel the compressed bearing ball out and only after cutting and chiseling a slice out of it it would turn to be removed. The aluminium alloy housing had severe pitting (one hole went right through), despite being isolated from everything (indicating uneven alloy composition). It will have to come out eventually, but since I had quite enough big jobs for this haulout, I epoxied it up with some International Watertite and cleaned up the insides to fit the replacement bearing ball (ordered from Jefa). It also turned out the rudder post was not built to the plans (available from Jefa's FTP server) and was a whole mm less in diameter than it should be. In order to fit future replacements, the local stainless artisan made a stainless sleeve to bring it up to the desired 64mm diameter. When reassembling, I further noticed that the aluminium tube that sits on top of the bearing housing (and thus the housing itself), was completely misaligned with the rudder post, which explains the very one-sided wear on the lip seal (also replaced). Not surprised Bavaria fired JP3 after seeing all this.
The upper bearing was absolutely fine, but its housing needed rebedding on deck as it had been leaking.
The new Jefa housing is made of plastic by the way. Their new roller bearing ball was well made to exact measurements, but is fragile due to the thin rim holding the rollers in place (I cocked one up because I hadn't sufficiently smoothened the housing and it got stuck in there, then the thin rim cracked upon applying some force trying to turn it back out - expensive lesson). After a very thorough second cleanup of the housing, it slid in well and there is no play at all between ball and housing or ball and rudder post.