Looks like you may need a new cable after all, since that white plastic bit is crimped on.
They aren't too hard to fit. To remove the old one you will need to undo it from the gearbox and then push it through the firewall (it uses an interesting grommet that's in two pieces; you pull off the outer hard plastic part then push the rest through into the car). Once the whole cable is through you just need to pull it out of the cluster whole. One possible problem is that the cable may be zip tied in place, if this is the case and you don’t care about this cable, you can simply cut the cable in half and pull it out both ways :devil: (remove the inner part first since it could be useful in the future).
Refitting is the reversal of removal. You feed it in from through the cluster whole, then get it to go over the heater (which can be frustrating, but there is plenty of room for it to feed through so it shouldn’t be too difficult), then push it through the whole and reassemble the grommet (two people are handy here so that when you put the outer plastic bit back on you don’t push the grommet back into the car) then reattach to everything.
Even with a new cable it’s probably a good idea to grease the cable before assembly.