Yep my money is on one or both of the ball joints on the bottom of the hub, mine makes the exact same sound and my mechanic said there was quite a bit of play in the passenger side one. It never used to creek like that until the wet weather we've had lately.
Only had the car a month or two and I bought a 12 month warranty, it says in the small print things like ball joints and pivot joints are covered so I'm hoping they'll foot the bill and replace at least one of them. Going to push for both as there is slight play in the drivers side too. Think they are about £80 each for the joints, but your looking at a good 2-3 hours labor per side to fit as they are apparently a bit of a pig to do.