I agree with Big John about the Jaguar dealer. They will have probably come across this issue and be able to carry out a fix.
As an alternative, I have a plug-in for the OBD port, it is a cheap one which works on bluetooth with my Android phone and when linked with the "Torque Pro" app it will show me the fault codes whenever I get limp mode. This has occurred once a while back, can't remember the exact codes, but it was linked to turbo boost pressure. It went away when I stopped and restarted and has not come back so far.
Please do keep us posted on the outcome, it is always useful to know.