Renault Megane 2007 Clutch Problem?

1.9l diesel with only 25,000km and always gentle driving and correct use of clutch, the clutch pedal height became lower and level with the foot rest rather than level with brake pedal. Also at the same time the clutch action now occurs very close to the floor, i.e. it engages and disengages in a very short distance from the floor (30mm). Up to this point there has been no clutch slipping occuring.
However, after taking it to the dealer for investigation, who advised the clutch is slipping and that they did not adjust anything, when I got it back I also can detect the clutch will slip (uphill in 4th for example) and more interesting that the pedal height is now almost back to normal and the clutch action is also back to a normal progressive feel rather than all happening 30mm from the floor.
Dealer advises need to remove gearbox to inspect clutch. If clutch is warnout, the repair is not covered under warranty.
Anyone with similar experiences?