The general consensus was that Jaguars shipped to the North American market did not require a four-digit radio code. And that is indeed true for my wife's 2006 XK8. However, my previous 2005 S-Type (which I sold in May 2018) required a four-digit radio code. Fortunately, it was printed on a card contained in the owner's manual packet....

 

Although remember that yours is an X150 and they have never had a key code radio as the radio is integrated. The X100 radio is a single DIN unit. I replaced mine with a Panasonic unit many years ago.

Richard

 

The radio code was provided with ALL X308 and X100 cars shipped to North America.(two plastic cards with the code)

I used to 'scratch' the radio code in the XJ40 and X300 bonnet under sides near the latch pins on the left side.(a few of us did that)
I also used to write the code in the owner's handbook if I remembered.

If the radio is configured to North America and stays with THAT CAR, there is no need to enter the code if battery power is lost.

If the radio is installed in another car, you will likely need the code.

If the radio is configured to another market (Japan, Australia, Europe etc.) OR configured with different features, (RBDS ON/OFF or AF ON/OFF) then you will need the code.

Customers were always losing (discarding) the code cards, (I don't know why)

Read TSBs

One time another shop called the shop phone and I answered. They asked how to get the radio code. I told them it needed to be research by the service writer.
Then I said WAIT. Look under the bonnet near the left latch pin, there MIGHT be a bunch of numbers scratched into the paint.
He called back and said THANK YOU, that was the radio code scratched, HOW DID YOU KNOW? (I laughed)