I attended an LRE day yesterday here in Perth with our D4 and 8 other vehicles (Disco Sports and Evoque) and one of the things the instructors strongly emphasised was "do not over estimate your vehicles capability in water".
We were on the banks of the Avon River at the time and the water was racing down over a crossing they use when the river is nearly dry, but never after the decent rains we've had recently.
Pity as it would have washed the mud off and saved the Cook a job......
AlanH.