The diesel is definitely the way to go given its combination of performance and economy. The two petrol engines also require either 95 or 98RON which, as you know, is expensive here.
The Premium Selection thing is also a good idea. First up, cars with an iffy service history aren't offered as Premium Selection, plus you have peace of mind if something goes wrong. 62,000km is also a lowish milage for an '06. All sounds good to me.