Found this on the net dude......
remove the leather gaitor first, by unclipping it from the bottom of the surround..
pull the gaitor upwards, so it looks like an inside out umbrella,
theres a metal clip at the top, you need to cut that off,
pull and twist up at the same time, it will come off with abit of force
remove the old gear knob fittings, put on your new knob and reverse the whole procedure, using a fresh jubilee clip under the gaitor the hold the knob in place...
drive.. holding your new knob.
IT IS NOT NECESSARY TO CUT THE CLIP. IT CAN BE PRIZED APART ENOUGH TO ALLOW THE KNOB TO COME OFF. JUST USE A POINTY OBJECT TO WIDEN THE CLIP OUT (I SUCESSFULLY USED A FORK).
THEN ON THE REVERSE PROCEDURE, SIMPLY SQUEEZE IT BACK TOGETHER WITH A PAIR OF CRIMPERS OR PLIERS.