Octavia Estate Mark 1 Parking sensors.

Read the very good articles on the forum about fitting parking sensors. Have now got a set but I am a bit worried about the correct positioning on the bumpers.

The article does not relates to an estate which is what I have so I think the measurements relative to the black bumper strip may be different.

I assume the spacing horizontally is ok .i.e 217.5 mm either side of the centre line then 445mm but I need to know the height above the ground or how far down it is  from the top, or is it the bottom of the black bumper strip.

Would appreciate some guidance.

Thanks  Pavarotti.