Control Room level Icon QCon problem

Hi All, despite using the mapping assistant I cannot get my Icon QCon Pro to control the Control room level - it always defaults to the main stereo output on the mixer.
Even if I go to the mapping, select control room monitor 1 level, click apply, etc.

Is there a way of getting rid of the stereo level link first? I’ve tried but it seems to just always default to controlling that.
Thanks for any help.