Where exactly is the non heated area of a Skoda heated windscreen?

I want to use the Sanef Tolling Tags for France , Spain & Portugal

I was told the the place to fix them was in the mottled area behind rear view mirror.

Tried using it last month and it only worked intermittently mostly had to remove from clip and wave outside car. 

You can see the old tag position from the black residual glue to the left of the mirror.

Well inside the blue marked mottled area.

I have noticed that there are two smaller less mottled areas marked red at the top of screen.

Is this where you are supposed to fit the tag.

Does anybody know for sure?

 

 

  

Edited 5 February, 20188 yr by vizslabob
spelling

Normally you fit right at the top of the screen, but I can't find any mention in the owners manual 

Can now confirm It works well if placed at the top of the screen in the Red marked area.