Hi Brand new here, but I have the same problom on a cargo 1.9 jtd sx. Left hand bends starts the wobble from 40 mph up to 55mph, also on acceleration, the harder the acceleration the worse the wobble. I have swapped all the tyres around, no change. local garage suspects nearside front drive shaft and there is certainly vibration under the passanger footwell. The garage was hoping to find a driveshaft supplier who could swap out the shafts, but can only find rebuilders, not good as it means my van is out of action for 10 days. Having read this thread though it looks like drive shafts may not be the problem. My van is on 05 with 65k miles, are the other wobblers of similar vintage/miles?
The wobble disapears as you reach 60mph, is this the same as the rest of you?
I did think that there was a lot of play to the rear most engine/gearbox mount. It is the one underneath near the middle of the van/car. Not sure if that is a cause or a symptom though.
Not sure what to try next....