Why not find a forum dedicated to this car?
http://forums.mg-rover.org/other-mg-motor-models-211/
This MAY help (Scroll about halfway down):
http://forums.mg-rover.org/mg-zr-rover-25-200-streetwise-101/mg-zr-rover-200-25-streetwise-rear-spoiler-high-mounted-brake-light-guide-485296/
XXX, January 2017