Kcl, your description sounds very similar to mine. Although to be clear on a minor point, possibly due to language, when you say a stiff "spot" do you mean a small section of the steering movement turning left is stiff, and all other areas are fine, for example;
<................................[stiff]..../\.........................................>
Or turning left is stiff through the whole range as mine was ;
<[stiffer][-----------stiff---------]/\..........................................>
on mine also add maybe 20% stiffer movement (loss of assistance) across the whole range on both sides
As you say, failing pas pump would give loss of assistance across the whole range at low rpm, or To put another way, less assistance the lower the rpm gets.
A difference accross the range from one side to the other, if there's no problem with a stiff ball joint or similar, can only be the steering box I would think...? No...? 
Once again though, I don't know for sure. There is a danger that you could change the box on my say so and it be no different, but if i had to guess, if it was my car, i would change the steering box.
I suppose the only way to know for sure is to change the box, for a known good one if possible.
As for mileage, I purchased my car with 65,000 miles on the clock. The steering was stiff when I got it, and I don't think it changed much by the time I replaced it at 90,000 ish.
I then changed the box from a car I have here with 120,000 miles on the clock, it had perfectly smooth steering.
So mileage doesn't seem to be a deciding factor. Although the car did have a higher ride height, with longer springs fitted when I got it. I wonder if this was deliberate as part of a rough road package or something, and the steering took a battering as a result of driving over rough ground...maybe? who knows. 
Thank you very, very much for your comments and help.
My problem is the first one in your drawings, only one stiff spot and all other places in the range are ok. BUT. It is stiff if I start to turn left from whatever position. So, from straight to left, stiff point, over that to full lock ok. Steering on full lock to right and when start to turn left, stiff spot and then everything is fine for the rest of the steering range.
I will be sourcing a second hand known-good box, this issue is driving me nuts. And, even if it would not cure it I would never ever blame anyone on this forum for giving the advice to change it
re the fluid change: I know it would have been good to change it all but only had one litre on hand, will source more and change it all. What is the total volume of PAS system? I remember reading 3 litres...?
Author
Topic: Creaking when turning (Read 2980 times)