The MGF and Freelander mirrors use the same 'mounting slug' bonded to the windscreen.
In the MGF it's part number is
EDP5642 -
Slug-windscreen mirror fixing - Genuine MG Rover at www.rimmerbros.co.uk
In the Freelander it's part number is
EDP5642L -
Adhesive Foil - Rr View Mirror Innr - Genuine Land Rover at www.rimmerbros.co.uk
As is often the case with common MG-Rover and Land Rover parts, it works out dearer (a whole 14p in this case) to buy the Land Rover one with the 'L' suffix
Either way, as the mirrors use a common mounting, they will be interchangeable.
The wiring of the MGF mirror and freelander interior lamp are compatible.
The Freelander interior lamp (as already said) is earthed through its mountings.
The Purple wire is a permanent live.
The Purple wire with the White tracer goes to the CCU, which 'fades' the interior lamps by controlling the path to earth (there's no direct connection of the interior lamps to the door switches).
The MGF mirror is similarly wired, as follows -
Black wire to earth.
Purple wire to permanent live.
Purple wire with Red tracer to the Multi-Function ECU (which performs the same interior lamp functions as the Freelander's CCU)
.