Luckily the digitizer still working and the serious cracks not really reached the screen itself, apart a small fracture from the clock area.
So, I decided to repair it somehow DIY, because a proper screen-repair could cost you around 120 GBP.
Step 1: Clean up the mess
some used top-up or sim-card
pen or pencil
clear liquid glue
Black acrylic paint
a bit of developed 35 mm film negative
good eye for details
iPhone screen protector (optional)
Firstly I removed the broken glass chips from the seriously damaged area with a tweezer. Under those there are the speaker and the light sensors.
I fixed the remaining shivers over the clock area with a model-kit glue,because I want to see the clock.