Sorry,but I have to make a comment about this as well.
Estate Agency was strictly regulated until 6 or 7 years ago. Only APIs could sell property,and they had to be Spanish as well as have qualifications. In response to EU pressure, the occupation was opened up to other professionals. The monopoly of the College of APIs failed partly on the argument that a person could sell their property without an intermediary, so it was illogical that only an Agente de la Propiedad Inmobiliaria (API) could introduce a buyer to him.
Unfortunately, we now see how wrong that theory is.
I understand that at the moment,new API members need a university degree in law or a subject related to property, and to take an internal examination. There are very few Brits who would be able to join. There are other professional associations which insist on members taking some sort of course (in Spanish).
Whilst honesty and integrity are the important “qualifications”, estate agents need training to enable them to exercise due diligence. The excuse “I didn’t know the houses were illegal – I just gave the papers to our/the solicitor” isn’t good enough. A professional should be able to spot a suspect property and investigate, and if he can’t, he shouldn’t be in business!