Clutch problem?

Low gears and reverse are very stiff to select when the engine is cold. This improves after the car is up to running temp but does not completely resolve it. No obvious fluid leaks. Gear change is smooth in higher gears and clutch biting point has not changed. I was told when I bought the car that the clutch was replaced at 90,000 but I have no paperwork for this. Any advice on what could be wrong would be gratefully received.