Kingsley. I have a similar van to you, and I intend to use the Grenadier to tow it as well.
I must admit I was a bit surprised by all of the comments about the steering, as I never got to experience any such problem on my drive day - however it was all off road and this may indeed be something only noticed on the tarmac. Perhaps this is the same experience as you.
I noticed the Carsales comment about the steering whilst towing, and I acknowledge that it got me thinking too.
I suppose there is no way to really know what it is going to be like until we get some impressions from the caravan magazines when they do their tow tests - or if our cars arrive before then.
That being said, I have towed 3T vans with many different 4x4/SUV's and there is NOT a perfect tow vehicle - everything has compromises. I would not rate my two LC200's that I had the best tow vehicles that I have owned, so that tells you something about towing compromises in the OZ market. Their OEM suspension was inadequate, and the GVM upgrades required made them steer far worse that I would imagine the IG being. (Yes I did dozens of wheel alignments to attempt a fix)
However, the IG has many many positives going for it in the towing space - Good low down torque, high payload, high tare weight of the vehicle, 3500kg tow capacity with 350kg on the ball, LT tyres, great ZF box, anti sway electronics, large wheelbase and track etc etc. However the main unsung thing which appeals to me is the short overhang distance from the rear axle to the tow ball - this will lessen many of the pitching and sideways movements that you can experience over undulations on crap OZ roads - but also keep the front steering axle more firmly planted on the road.
Ineos also at this stage will be allowing usage of a WDH if such a device is needed.
I my mind, the Grenadier has been designed as a high load tow vehicle from the outset too, so they must of tested it and deemed the drive experience acceptable. Also the steering "feel" seems to be inherent to the IG due to the ball steering so I am not too worried that towing a van will exacerbate the problem. Also I have noticed that in some videos, the steering doesn't seem to be an issue at all.
Guaranteed though, after this round of press releases, INEOS engineers are looking into any perceived problem in this area.