[GeoffWW]

After seeing Lottysvdub's idea above, this morning, I decided to give the rag idea a try. I had no luck so I used two flat garden trowels slid in from either side, one above the spindle and the other below. These were done with the adjuster knob in the "centre" of the adjustment.

After a couple of strong jerks on the handles the knob came away and two 'half-sleeves' shown in pics 1 and 2, came away from the rear of the knob. This is my first entry with photos, thanks to Arctic's method. the third picture is looking from the seat-side of the knob showing the splines.All I have to do now is replace these parts onto the spindle end on the seat-back.