My book shows the following species to occur in NE Spain:
griseola
caniola
uniola
rungsi (v. local)
pygmaeola
palliatella
pseudocomplano
(
complana)
lurideola
(
depressa)
From the description given,
uniola, the silky footman, seems an equal possibility, though it is more local than caniola. Your picture certainly shows a very silky texture. Size might be a clue:
caniola, male wingspan 26-32mm;
uniola, male wingspan 18-25mm, so noticeably smaller.
I know very little about moths and I'm only butting in because I've got a good book...
Guy