TD4 Manual - Stiff Clutch

Hi - I have a MY16 TD4 manual Evoque with 35K miles on it. Recently the clutch has taken to becoming very stiff when restarting after a long drive (circa 100miles). After 4 or 5 clutch presses it frees up and all is OK again.

It's still under warranty but my dealer wants to replace the entire clutch and flywheel assembly and the JLR won't confirm it's covered until it has been removed and inspected.

Has anyone else experienced anything similar, I'm suspecting some form of hydraulic issue?