I happened to see a mention of someone who does a bluetooth conversion of the OEM radio in the X300 on a "book of faces" post.
However there was no mention of actual contact info other than to say this could be found on evil-bay
I have searched there for "Jaguar radio bluetooth" but so far I have not found anything.
Anyone know anything about such a conversion?

I have in the past put an aftermarket radio in a XJ40 car that I own but I was never satisfied with the look of the resulting change in radio head units.

 

Bluetooth transmission is missing the full input signal ( this has to do with data or refreash ( ? ) rate ) so a direct inline plug is better

There or some post on the inline jack you can solder in ( original Jaguar head ) losing the cassette function

 

Are you saying that others have made posts about how to solder in an aux jack in place of the cassette function?

 

Yes