Update: This is very easy plug and play installation.
All you need to do is to plug receiver into instrument cluster from behind.
Then wait a couple of days and you'll see antenna mast symbol. This means that your clock is now in radio controlled mode.
In this mode you can't adjust minutes, but you can adjust hours. By this you're effectively telling instrument cluster the delta
between your local time and the CET time in Frankfurt.
And you don't need to remove dashboard for that. You can only remove lower trim where your knees are
and there's just enough space to connect electrical connector from the back of instrument cluster via removed knee trim opening.
I found that reception in the standard receiver location under centre of the dash is not very good perhaps because I have a-thermal heated windscreen.
Decided to secure the receiver elsewhere in the car, perhaps behind the lower right panel where most of electrical fuses are.
Undecided about exact location yet.
Pictures!
To be continued ...