Power steering problem

Hi all,
I am having trouble with the power steering on my 1999 Petrol Freelander.
When starting from cold the steering wheel rocks/shakes quickly left and right when I turn the wheel reversing out of my drive onto the road. Once the engine is up to temperature it works fine, no shaking at all.
I am not losing fluid and there is no significant noises from the pump or the rack.
Any ideas, all advice gratefully accepted.
Cheers

One side harder then the other to turn when cold? I never tried this but they make power steering cleaning additives...

No, Makes not difference if I am turning left or right as soon as I slightly turn the steering wheel it it shakes, rattles, or rocks back and fro(however I can describe it) in my hand.
So I was wondering whether she had air in the system but this would mean she had a leak and she is not losing any fluid and I have not disconnected any pipes etc, or whether the Steering Pump had a problem, but she doesn"t make any unusual noises, or whether the Rack was at fault. The problem came on shortly after it had been standing for 2 weeks in a multi story car park.
Any advice welcome.

Are you able to post a video this looks like easier to troubleshoot that way.

Is you go straight out of you driveway, does it doe the same thing instead of backing out?

Do the wheel move when the steering shakes ? No different noise from the steering pump ?

Engine being to temperature could also mean high rpm driving the fluid steering pump and warmer less viscus steering fluid..