Jag S Type 1999, wont't start after replacing Steering Column Lock XR813537. Fault code P1260 Theft detected. Engine does not crank

[Rob_Reilly]

The ignition switch is mated to the car. You probably will have to keep some parts of the old switch in place.
Read this.

Ignition Switch Removal

On my 2000 year 3.0, when I pull the ignition key out of the lock there is a little flap that is supposed to close. Sometimes it doesn’t, and I have freed it up by spraying in lock-lube graphite. Now today the radio and clock stay on, there is a chime when I open the door, and the remote locking doesn’t work, although I can lock the car with the key in the door, so all the electrical locks are working, but not the red light on the dashboard. The chime stops when I close the door, and I turned of…