Sounds like your THRUST bearing to me.
I've got the same problem on my Disco 2 TD5, more noticable when the car has stood for a while, once the cluctch has been pressed a few times it goes away. Been doing it for ages just cant be arsed to pull the gearbox off to change it. Cheap as chips for the Bearing but may as well change the whole clutch whilst the gearbox is off
Brian
