It's interesting to see the difference. The Australian editor at Egmont felt this was better suited to their market than the UK cover.
On the question of how much say the writer gets over the covers with large publishing houses, the answer is very little. However, I view it like going to the hairdresser. I pay my stylist, Alan, to know exactly what he's doing and what will work with my hair so I tell him the approximate length I want it to be and then I leave him to get on with choosing the style because he's the expert, not me.
I'm happy with both of these covers, but it was fascinating to see how differently they turned out.