The feed rollers after ~75 years had become very hard and D-shaped instead of round. This made paper feed a very random affair. Even though the machine comes with a "World Service", it's out of warranty by about 74 years.
To get the machine to feed properly again the back-rollers have now been replaced with new 'rubber' from several layers of heat-shrink tubing (in-expertly). The platen is a bit hard (noisy, but not a big issue) and seems to have worn or shrunk un-evenly (makes the paper want to go awry on linefeed). Over about an inch on the left-side of the platen it is about half a mil smaller in diameter than the rest. After having tinkered with the rollers, I'm not tackling that or taking the carriage apart in any way however.
The machine works again, cleaned and with new ribbon on the spools.
A very explicitly mechanical machine that lasts. Should be good for another 75 years :)