Got a problem with my Ulysse - above 2000rpm there is a whining/rattling sound from the gearbox/diff area and the car will not pick up any more speed.
I have jacked the front of the car up and 'driven it' and found that there is little or no drive to the passenger side wheel.
Anyone got any ideas ?

Did you jack up both sides? The differential will not drive both wheels evenly when not in contact with the road.