Jaguar X-Type vague steering

I have a facelifted X type diesel with 14K miles. It has never been curbed or been in an accident. Tyres fitted are P0's with good even tread wear.
Just recently the car has started to pull to the left, with wobble through the steering wheel at low speeds. It has been into 2 main dealers. Tyre pressures, front wheel tracking and even moving the front sub frame to the right to counteract the left pull have been tried to no avail. Dealers have now said there is no problem with the car and that it is a normal characteristic for the vehicle. They even took me out in an identical model that had the same issues, and told me it must be normal as two cars are the same. Service person told me that I may wish to try some tyres with a more forgining sidewall such as Yokohamas. What service!!
This has now made a very good car into one which I believe to be a horrible driving experience.
Any ideas or has anyone experienced the same probles.