Hello, I'm sorry you haven't received an answer sooner, I hope the following assists you.
If the clutch is hard to press and this is resulting in damage to the hydraulic system then there is a concern with the clutch assembly itself, usually a cover or DMF fault.
You need to remove the transmission to replace the clutch, also check the dual mass flywheel (DMF) to make sure this isn't causing damage to either the clutch or hydraulic system as DMF failures are very common on this model. Check the fork that operates the release bearing, make sure the pivot isn't worn allowing the fork to move about excessively.
When you refit the clutch slave cylinder make sure the rod locates in the release fork as I've seen a few where the cylinder rod is not in line and this causes the slave cylinder to crack and fail.
Start with removing the transmission and checking the clutch, DMF, release bearing and fork condition, as you are suffering repeated hydraulic failures the fault must be outside the hydraulic system.
Let me know if I can assist further or if you have more questions regarding this and I'll reply as soon as I'm able to.