Could try disabling it using your Emergency Key Access code, which should be with your original paperwork or is available from your local Rover dealer (Got mine free) on producing your registration documents.
The code is entered into the car by a sequence of turns of the drivers side door lock (ie; two turns left, one right, seven left, nine right or something). This disables the alarm function, but still leaves the immobiliser active, so the keyfob still needs to be near the ignition to start.
Otherwise, the people at http://www.mg-rover.org are very friendly and helpful.
Lee, September 2006
