I would think there would have been a useful cost saving for Rover too: a small stainless steel blanking plate vs the cost of a lock barrel, associated linkages and microswitch.
When I bought my 420 GSi Turbo in 1997, the previous owner had given the driver's door handle the same treatment (as well as fitting a Thatcham-approved immobiliser that required me to poke a sensor on the dash with a stick attached to the keyring every time I wanted to start the car).
Getting into the car after the battery went flat was challenging, to say the least. It involved using the key to open the boot, unscrewing one of the rear speakers and then poking a modified broom handle through the speaker hole so that i could 'hook' one of the rear door lock buttons upwards!
