Of course if the engine or gearbox has got to come out to change the slave, a good inspection of the clutch is needed- maybe pop a new one in at the same time while its dismantled.. I think i would. Daves suggestion to do both slave and master cylinders at the same time is very sound advice - if not done chances are the old component will soon fail. Stress caused by the new component being the reason.
All very involved when a clutch slave is ideally fitted along side the gearbox with 2 bolts holding it on - need an MGB for such simplicity!
