I am getting a pulsing sound, sort of like a fan slowing down then speeding 
up (not a brillaint description I know) coming from what seems to be the 
power steering when I turn  the wheels.

I very rarely happens in the morning, but when I am parking the car at night 
it is nearly always there. It doesn't appear to be doing it during normal 
driving, but I am not sure whether it is the engine drowning the noise.

 A garage recently checked the steering rack/column and it briefly 
disappeared

Any ideas?

Tony

Power steering pump? On my old Laguna it whined like a banshee and was
quieter when the hydraulic fluid was cold first thing in the morning.

Chris