@Wrong-Wheel-Drive I ended up jacking the car up and spinning a wheel, definitely something near the diff for sure. Car is at the shop now so hopefully get some info soon.
Also, oofta at getting an open diff when you pay for an lsd.
Theres a red turbo esprit a lot like that sitting on the property next to our new horse boarding facility. But it appears to have been brought from California to Texas and then parked in the grass with a towel over the rear hatch.
Mercedes call it the "Wet Skid Circle" essentially a skid pad, which if you've never been on one before you'll massively underestimate the sheer lack of grip they have, I've never driven on ice but I would guess its fairly similar to being on ice