No success. Different company. Very polite people though.
Anyway, I've pumped oil in everywhere. In most places it just goes in and flushes out the grey/brown stuff. But in some places the oil doesn't go in, it gets spat out. I'm assuming this means that I've to engage that lever before the oil can go in, or something.
It's made a difference, the main saddle is quieter to move. And the slides feel, slicker, I suppose. I've also figured out why the main saddle has a 'skip', it's the rack bolted under the bed, as the gear moves from section to section, there's a miss beat, almost, that I feel through the wheel. Perceptible, but not an issue, and, since I've oiled the gear, nearly gone.
I've still not looked at the drum switch yet. Time is precious.
I'll get to it.