I ended up buying a digital 90 euros CO detector, so far seems promising.
Remember that in Europe, the installation of a CO detector ( even a “sticky on one” ) is considered a modification. To remain legal, you / maintenance organisation have to follow the guidelines laid down for its installation.
I’m not a licensed engineer but that installation on top of the glareshield does not look legit !!!
Slightly off topic but the compass deviation card also appears to be missing !!!
VFR