The Spanish Land Registry publish a Guide to Buying Property in Spain. Spanish Property Insight provides information and advice on buying a property in Spain.
Expat forums, English-language newspapers and talking to local residents including other British nationals who have already made the move can really give you a feel for an area and give you the inside track on any local problems.
The Spanish Ombudsman is responsible for defending the fundamental rights and civil liberties of citizens by monitoring the activity of public authorities. If you have a complaint about any public authority, you can submit a complaint to either the regional or national ombudsman. If you are facing problems with your property in Spain, there are many residents associations who may be able to provide support and advice as well as put you in touch with others who have had similar experiences.
Disclaimer: This information is provided as a general guide and is based upon information provided to the embassy by the relevant local authorities and may be subject to change at any time with little or no notice. The FCO and the British embassy will not be liable for any inaccuracies in this information. British nationals wishing to obtain any further information must contact the relevant local authority.