Hello Simon,
I might be not in the position to critique your work since you are a much better photographer than I am, but I'm not really impressed by this photo of the Amarok. It has a very 'decent' feel to it (which in itself is not bad) and it gives a good representation of the car but it looks also somewhat boring and lifeless. Technically (sharpness, color correctness, lack of distortion, etc.) it's very good, artistically you could have made a lot more of it.
The lighting looks somewhat flat, everything is equally lit. The elements in the foreground are competing for attention, you could have made those darker. The color palette is all over the place, lot's of satured yellows, reds, blues... very little harmony. A monochrome, complementary or analogous color scheme would make a huge difference. The composition and perspective are not very exciting in my opinion. I like the environment, it totally suits the car although it would be cool if there was some action going on, a person using the car as a workhorse for example.
It's easy to critique while it's very hard to make these kind of photos, I know. If you don't appreciate this comment, just ignore me.
By the way, I really liked pretty much everything of your previous photo of the VW's! Both you and Lightfarm did a really good job there.