In reply to VS4b:
I have a different estate with the same roof rails. I decided not to go for the aero bars in the end as I was intending to pad my bars with foam, so it seemed pointless. I did go with Thule, and think that it was a good decision, they are really well made and easy to put on and off. They come with locks as well. I didn't want to risk the cheaper ones, they seemed flimsy in comparison.
Roofbox.co.uk were great, good service and well priced.