Spotting

that looks pretty good - I think we got the genus

Thanks, Ioarie ( In remember your face, but not this name... :-)), that was also my final guess, but had still troubles with the species name.
Gonioctena variabilis was one of my candidates, but Lisbon is not within the range:
http://www.biol.uni.wroc.pl/cassidae/Eur...
http://www.galerie-insecte.org/galerie/v...
All these beetles are extremely variable and show sexual dimorphism. Key issue for me was always the yellow color of head and pronotum. Most of the Cryptocephalinae has a black head/front.

My final guess so far would be female Gonioctena pseudogobanzi.
http://www.biol.uni.wroc.pl/cassidae/Eur...

I take the risk for making a suggestion to open further discussion and try to get a confirmation.

What do you think?

compare https://www.inaturalist.org/taxa/468938-...

Not exactly sure about the family and genus, but it reminds me of Chrysomelidae, Cryptocephalinae, but no match found.