Landcruiser IFS and Water Warning

I have a turbo diesel landcruiser which damaged the fan and radiator to the tune of $1400. I was crossing the upper reaches of the Murray River at Tom Groggin in about 500mm (20 inches) of water and the fan blades "propellored" forwards and have broken off and also damaged the radiator. Could it be that the design of the independent front suspension, now stardard on most landcruisers, results in greater inflow of water though the radiator during water crossings?

I have had discussions with Toyota regarding the situation and they say that it is not a manufacturing fault so they have no responsibility to repair it. I wonder if the design of the bash plate underneath the independent front end, that is 28cm off the ground, and angles down at around 45 degrees near the back edge, causes a wave to form at the front of the radiator and then enter the engine bay. I put this to Toyota and as of yet a response has not been forthcoming other than it is "not due to a manufacturing defect" and that the vehicle is "not a boat". I would have thought that with a wading depth of 700mm I would have been safe, as 700mm approximates the mid point of the fan from the ground.

I wonder if the new V8 IFS Landcruisers will suffer the same fate as I imagine their underbody is very similar in design. Toyota suggested they will review the situation if I get an engineering report. What options do I have for repair and reports? - I am loathe to spend $1400 ( approx fan $250 and radiator $900 plus fitting) if I could suffer the same fate again.