Vasilis STERGIOS le 29/10/20
Vasilis STERGIOS le 02/11/20
Thank you @Frederic-ANDRE for the suggestion. It does appear to be a close match - still the number of cups branching within a single form is puzzling. Will have to do more research on the subject.
Frédéric ANDRÉ le 29/10/20
May be Calyx nicaeensis (Risso, 1826), https://doris.ffessm.fr/ref/specie/209