Using x mirror with shape keys


I have imported a mesh from makehuman and I’m currently creating some expressions using shapekeys with the help of the sculpt tool. I’m trying to use the X mirror tool but is doesn’t seem to be working. I’ve done this many times in the past successfully . I know proportional editing needs to be disabled so its not that. I was wondering if I have another setting disabled without realising

Thanks in advance

If you are using sculpt tools use the symmetry options in the sculpt tool panel

Thanks you