With the wiper motor sorted it was time for the wiper wheel-box, which didn’t look that good at first glance;
But after a thorough clean-up with degreaser, wire-brush and sandpaper, and a bit of black paint they (together with the tubes and the spacers) again looked quite acceptable.
Only (slightly) bad bit being one of the wheel boxes’ threads, which is damaged by contact corrosion with the locking nut. To prevent this in future I used some non conductive anti-seize-grease.
So another few bits ready for assembly once the body is back from the paint shop.