Jack up front end and put on axle stands, remove front wheels and lower engine cover so you have a bit more room to work, remove battery and airbox, pull off clutch cable from the gearbox release fork, make a note of how and where the cable is routed, i think there is 4 or 5 clips to remove from the bulkhead heat shield/insulation, some of them unscrew and some of them you need to lever off, you need to pull the insulation away from the bulkhead so you can get your hand down there to grab hold of the cable, now inside the car above the brake pedal you will find the clutch cable self adjuster mechanism, push the cable end out of the securing clip, tie a bit of string around the end of the cable as it will make it alot easier to find the hole through the bulkhead when fitting the new cable, the cable is also routed awkwardly under and behind brake pipes, now you need to release the outer cable end that goes through the bulkhead inside the car behind the pedal assembly, you may find it easier to remove the inside brown insulation behind the pedal assembly so you can see the hole the cable comes through easily, it is held in with a couple of wide headed plastic plugs with hexagon heads, to release the outer cable you need to squeeze in together the 2 plastic wings that pop out when the cable is pushed through the bulkhead hole, the 2 wings are very awkward to get at and squeeze, you may need someone else outside of the car to pull the cable out, attach the new cable end to the bit of string and pull back through the bulkhead hole, when the new cable outer end is inline with the hole you need to get your hand/arm down between the bulkhead and insulation with the palm of your hand facing the bulkhead so you can get a grip of the cable, now shove the outer cable end through the bulkhead hole until you feel/hear the plastic wings pop out, refit cable along original routing points, take care when refitting the cable into the white plastic clip on the bulkhead as they can break easily(oops), pull inner cable end around behind the pedal assembly and secure in the clip, refit the other end of the cable into the gearbox release fork, now you will find the clutch pedal is on the floor, push it up and down a few times as it is on a self adjusting ratchet mechanism, now refit everything else you have taken off.
Phew - lol.