This is a old thread but I think it gives the right explanation for the issues I am facing with my steering and the inability to adjust it correctly.
When my Jag has been parked over night (so it is completely cold), I can turn the steering wheel maybe 1,5-2 inches without having the tires actually move, this is accompanied by a nasty rubberish squeaking from the steering column/rack. When the car has been driven for maybe a mile, that play has gone, it's like the steering rack gets fixated again at an (un)certain position. And that explains why several times the steering wheel was perfectly centered after a professional 4-wheel alignment and the very next day it wasn't centered anymore!
I still think it is a little strange that the steering rack play can only be detected when the car is cold, but maybe the heat from the engine somehow reactivates the steering rack brackets bond.
I have been looking through various parts catalogues, but I cannot find these brackets or any kind of bonding related to the steering rack. The steering racks themselves only have the mounting points, so I think simply replacing the steering rack (which in my case is in very good condition) would not solve the issue, would it? I found a supplier for the aforementioned STEERING RACK BUSH REPAIR KIT, but I am wondering if this is really a longlasting solution?