Diff or Gearbox at fault

This is all good - but if the gearbox is in neutral - why would a driveshaft be influenced by the engine at all? It may vibrate simply through the whole engine/gearbox/IRD "lump' vibrating - but not due to any form of mechanical drive and would not be influenced whether the clutch was engaged or or.

As Nodge says, maybe 2 different faults - both major faults that both happened at the same time with no prior warning as the car drove OK, or maybe the driveshaft issue is a non-issue and a red herring.

If the driveshaft support bearing has collapsed possibly leading to the diff failing - surely this would have been obvious driving the vehicle previously - they don't suddenly collapse.

A video of the driveshaft making oval shaped movements while not rotating and with the car in neutral and stationary would be good.

Hi,
Just wanted to say thanks for all the comments regarding the fault. After a few no shows, an ex-mechanic came and looked and said it was 'more than likely' the drive shaft. Quick search found a few options price wise from breakers £30 to LR almost £800 I think was quoted Breakers it was, as we still weren't sure if that was/is the only problem. So tonight, before the snow was due, part fitted by said mechanic and his mate, less than an hour later all done and car moved for the first time in over a month. I'm hoping this is now sorted and I can now look at getting the rear prop fitted and have a 'sensible' 4wd SUV
Cheers again to those that knew what I didn't

Interesting problem. Thanks fer letting us know the fix.