The cable-covers between the rear door and pillars have gone white. Just me? TSB? Thanks!

Did you try cleaning them and treating with rubber preservative?
Ours have done the same but I assumed it was just the mold release compound and I didn't worry about it nor have I tried to clean them yet.

Same here. Wondered what the heck it was.

It's normal. Hit it with some armorall or 303.

Scrub and it will come off, and/or then hit it with some VRT (vinyl, rubber, tire) protector

Noting the problem is just with the two rear... The two front are fine. Anyway now I know where the white-flakes in the door-jams were coming from. Had to scrub with Fantastic and a toothbrush to get this stuff off! Seems wrong to me.