Tom:
Seller needs to provide to you records of IBI ( Local Tax on Property) payments where you will find the Cadastral value of the property.
Then you will have to multiply the Cadastre value of the property by an index which is determined annually.
For Cataluña, calculator of Tax Value of the property is here:
Cataluña
Notary fees of Mortgage deed, are according to Spain Supreme Court, applying Consumer Law arguments, to be paid by lender excepting a copy of the deeds that needs to be paig by the mortgage loan creditor ( consumer)