Gear knob off, 4 x 3/8" nuts off where the gear lever attaches to the chassis, long 1/4" UNF nut and bolt off the central mounting at the bell housing, drift the roll pin out of the selector at the back of the gearbox, move the whole gear shift rod back until the gear lever can come through the hole where you adjust the hand brake cable (centre of the chassis where your elbow is when driving), and you can replace the bush where the lever attaches to the rod from inside the car.
There are two different types of bush, plastic and brass.
Don't drop anything into the hole in the tunnel or it will take you ages to get it back out. Plastic and brass are not magnetic.