On the VY those knobs will come off with a flat blade screwdriver (or two) inserted behind them and GENTLY leavering them off. I repeat, on VY! Don't know if yours are the same. Then the plastic clip half way along the seat trim can be removed with a flat head screwdriver, turning it anti clockwise 1/4 turn. Then in behind that clip there's a phillips head screw that needs to come out. If you have electric seat, you'll need to unplug the wiring harness last of all. But all pretty easy. BTW my reclining knob is about 90 mm in diameter, so if yours looks the same, it should just come off the same way. To put it back on just slide it over the spline till it stops, then give a good thump with your hand and it will click into place.
'Ah well, I suppose it had to come to this.'