This seems to be more difficult than expected.
Because I have no experience with Spanish Coleophorids, I asked Ignac Richter. He works with this group since many years and he has a good site for this family: go to http://www.coleophoridae.bluefile.cz/?page_id=5800 , then select "European checklist".
He proposed Coleophora turbatella. If you compare drawings of male genitalia in Toll´s paper (the link is present on Coleophora turbatella-page in BH of Lepiforum) and also photos of male genitalia on Ignac´s site with your slide, the species which fits best is C. turbatella. External appearance do not really fit, externally C. albicosta is more similar. Coleophora albicosta feeds on Ulex europaeus. If this plant is present at the finding place, it is a good argument for this species. If Ulex is absent there it should be another species.
I am looking forward your answer, Peter