There are a couple of alarm bells being set off here. The first is that the engine, if driven through water deep enough, may have ingested some of that water which has caused what’s called hydraulic-lock. This is usually terminal and involves the (non-compressible) water, bending or breaking the engine’s internal bits and pieces such as the crankshaft and connecting rods. If the engine won’t turn over at all, this could be why.

The second possibility is a little less scary and involves the flood-waters entering a part of the car’s electronic or ignition systems, leading to a short-circuit. If that’s the case, the parts can sometimes be dried out and the engine will restart. In modern cars, however, once the computers and other electronics have been wet, they corrode internally and will need to be replaced over time.

This is part of the reason that insurance companies tend to write off flood-damaged cars, even if there’s no other damage. Insurers know that a car that has been under water will come back to haunt them in the longer term as all sorts of electronically-controlled components go belly up.

As you say the Great Wall utes are new to this country, and so far too few have made it on to the market to give us a good picture of what they're like. Having driven them when they were launched last year I can say they are at least one generation behind the current market leaders in that segment, but they seem reasonably well built and they're made from parts that are mostly hand-me-downs from other makes and models, so they should be well tried. At the end of the day you would be a pioneer if you bought one, going where few have gone before, but given your budget it's probably worth a punt.