Hello Frits,
if I didn´t overlook any important information in the WIKI, then it should be Ischnocolus valentinus, the only Theraphosidae occuring in Spain. As there are no visible spinnerets, I would exclude Macrothele calpeiana, the other Mygalomorph species in Spain.
Cheers
Jutta
EDIT: Sorry, I didn´t see Ulrichs determination, when I posted my ideas, otherwise I wouldn´t have posted it.