Hi I realise that you posted this 2 years ago but thought you might still be interested, I have recently had a problem with My C5 2009 (138) I took it to the main dealer, they were adamant that there was nothing wrong with the clutch, we took it for a test drive but couldn't get it to slip... I took it back 2 weeks later, they would only look at it if I agreed to pay for the removal and reinstatment if there was nothing wrong. this was in the region on £400. If the clutch plate was worn I would have to pay the lot! just short of £1000. It turned out that the fly wheel was warped and the cluch was 40% worn. they fitted a new one free. however I had to pay for a new plate as Citroen wouldn't, I tried to say that the plate wouldn't be as worn if if it wasn't for the problem but they wouldn't have it!!! £295 for materials!