Hi Ian, Was hoping someone might respond to your problem as they have not, I googled your problem
The squeak comes from the bushes that connect the horn etc
remedies one is to add an additive to the power steering fluid, available from Jag dealers, people say that it cured it
also some people have tried lubricating these bushes, but you will have to google to find the answer how to do that
Lastly, someone changed their steering rack and that cured the problem
Hope the above has helped and that you get the problem resolved, keep us updated,
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