Advice on property purchase please.

We are in the process of buying a country property in Andalusia and the house is 10 years old.

Our solicitor has advised that the swimming pool and an extension wer not included at the land registry so the owners  have now applied for a DAFO.

Our Solicitors  words.

"The Property is located in rustic land. That is why the vendors after signing the private purchase contract are asking for a DAFO to the Town Hall, assuming all the costs. The DAFO is a kind of legalisation of constructions that has been built after 6 years. Please note that the Town Hall won´t allow in the future, any kind of constructions, alterations or extensions to your Property. You will only be allowed to do repairs. This situation is quite common in the “campo” areas. The vendors have already asked to the Town Hall a certificate stating that the Property is free of planninf charges and sanctions."

1. Does this legalise all of the non registered additions. And the property becomes 100% legal with no come backs.
2. What would happen if the house burnt to the floor - can you rebuild it or is this prohibited under the DAFRO?

When viewing the property we noted that the septic tank was on a parcel of land over the small acess road (which is an access road to our property and three others) we were advised by the estate agent that this parcel of land was included. Subsequently our solicitor has advised this land is not owned by the vendor so the  septic tank isn't on the land registered for the property.

Any advice on this would be much, appreciated

Paul.