The one on the first site (at least from the pic) is a Nintendo made one, the ebay one is a third party one. Given some problems I've heard about third party component cables, I'd use Nintendo's.
But that 1st site looks suspicious... (maybe just cause its british--haha just joking), you might want to get the cable from Nintendo's online store, that's where I got mine. They ship really fast.
EDIT--Don't you guys in europe have that weird "scart" thing that gives higher quality video? Might be a better choice if your tv supports it.