Clive ) gurgled happily, sounding much like they
were saying :

That got me thinking - It's the rears that are driven, not the centre
wheels - so if grip was somehow lost at the centre axle, and power was
not reduced quickly enough, a jack-knife would be eminently possible.

I understood the engine to be in the back but drove the rear wheels of
the front unit through a cardan shaft to stop any chance of imbalance of
drive.

Makes sense - Merc's website confirms it's rear-engined, but just describes
the "rear axle" in the transmission specs - which could mean both rear and
centre axles are driven - which would give the same effect if the centre
lost grip.

I seem to recall reading that the MoD had similar problems with powered
trailers on 101 Forward Control Land-Rovers "pushing" too hard and rolling
the vehicle, so they dumped that idea.