I have the same exact issue. It sounds like a boat sometimes
I've also had people telling me it could be air within the system. Honestly I've just learned to live with it, mostly because I assume it's rack n pinion related and so, I'll tolerate it until I don't or until the car fails an MOT because of it.
But I had never heard of the UJ theory near the turbo. Which one is it again? so I can check!
Mine does it mostly, if not exclusively, when the car is still or going pretty slow, like parking.