Key Stuck In The Ignition. Jaguar X-Type 2002

I just bought a Jaguar X-Type 2002, the problem is that key is stuck in the ignition. I've been unplugging the battery everytime I take it out. My best guess is that the shifter does not recognize its on park. The mechanic said we would need to replace the entire shifting mechanism. It would cost me about $400-$500, he also mention that this might also be a cable or linkage from the shifter to the transmission, How can I check and/or replace the cable or shift linkage maybe its damaged. Is there a quick fix, such as a disabling a fuse, or unpluging a cable that will allow me to take out the key whenever. I'm even thinking going redneck style and wiring my own fricking switch to disable the current.
Does anywhere I can get cheap parts for a Jaguar X-Type, because I also need to replace a front bearing.
I'm thinking about replacing it myself if I have enough free time? Where can I get some diagrams of either the shifter, or instruction on how to replace a bearing since I've never done it anything like it.

Also, while driving an X-type at normal speed/RPMs (around 2000) are you supposed to feel a slight launch when the automatic transmission changes gear, similar but a lot softer than a manual transmission.
How can I check for potential future problems.