Hi Victor, these guns were imported to the UK, most of the times in the rough then finished by various makers in the UK. They were then sold thru various dealers. Look on the bbl flats and you can find the makers mark and date code. Here's a link to them:
http://personales.jet.es/rafa/b_punzones.htmlAs to quality, Spanish guns from this period run the gambit from best to dogs. Sometimes the gun looked great on the outside, but the insides were another story....to long to go into here.
Anyway, good luck!!
All the best!
Greg