2003 Jaguar XJ8 Passenger Door Ajar Warning Light

My alarm is going off at intermittent times and I'm seeing a 'passenger door ajar' on my dash.

I understand there is a microswitch in the doorlatch, but when I look up for a part to replace it, I'm only seeing the lock actuator or lock module, both of which are $300. Is there a switch (for less) than I can buy and replace in the door that will stop the error messages?

Thank you.
Dave