lost all drive on peugeot 2.2hdi boxer van, 03?

I lost all drive when driving, there was a metalic grind then drive gone in all gears, i was towed home by RAC, later on same day i tried it again, it made the same noise & then moved as normal, i have since lost all drive again. The clutch pressure feels normal & gear stick feels normal, allthough the noise occurs at a certain position when clutch pedal is released. when engine is off & in gear it just freewheels