[Closed] Mirror without Inverse Scales no longer Mirrors

I have this script, the problem is it’s not working.

for x in selection do (

MyPosition = x.position
MyRotation = x.rotation

x.rotation = (quat (MyRotation.x) (1-MyRotation.y*) (MyRotation.z*-1) (MyRotation.w))
x.position = MyPosition*[-1,1,1]
)

When I run it, the objects jump across the X axis as it should, but it doesnt mirror at all – I have tried All sorts of combinations of inversing Quat axis, and nothing so much as helps.

Any help would be great, Ive been really frustrated with this.