P38A Disel Auto shifter cable change

Hi, has anyone changed the shifter cable, mine must have stretched as I cannot get 1st or if I adjust to get it I cannot get park, the shifter lever has full travel hitting the plastic both ends, the bottom end looks ok but is it a hassle on the top side? Its been like it ages with no 1st gear but one day I might just need it. The manual makes it sound not too bad a job but is it really?

have you checked were cab;e is attached to the mount

Not 100% as I have been doing it on my own, and never really checked the C clip, will check that out first, that would be nice, thanks for pointing that out.