One of the seat mavens, if we have any!

I've got a driver's seat with a tatty back, and a spare passenger seat. I've separated the back
from the bottom of the spare, so the basic swap is straightforward. But the tilt knob will end
up on the wrong side of the new arrangement.

So the question is how simple is it to remove the tilt spindle and turn it end for end?

I've got the knob off, removed a circlip from each end which had looked sufficient to retain it,
but it won't shift with moderate effort. I wanted to avoid removing the cloth casing, because
that will only open a wormhole into a whole other sub-project.