from my experience with spanish "installations" they all should have an rcd fitted,so if you have one already sounds like its faulty,
1/how old is the building? will give a rough idea on condition
2/get another sparky to do an insulation (ir) test on all conductors as recommended
3/save up for a rewire
sorry mate but you may have got an expensive problem,be carefull who you use as i dont think they have gordon browns stealth tax over there (part p
)
harmonisation !!! thats a joke aint it-"do as we say" and that