Permanent or temporary?

You can just disconnect at the small white connector under the trim on the screen. Fail-safe is non-dimmed.

Put a switch in the power feed at a point further back in the dash loom.

Put a switch in the reverse override supply to swap from reversing lamp to 12v feed.

Unfortunately both the power feed and reversing wires are the same colour (Bk/Rd IIRC).

Don't know why Ford deleted the Mk3 Mondeo 'auto' switch.

Martin