In my book, page 208 I mention the baja de residencia (I referred to it as thebaja consular - same thing), which means (loosely translated and in this context) the form on which you swear that you are giving up of your "old" residential address to live now in Spain.
The following is written by Sr. Carlos Formby of the British Consulate in Malaga (in 2006) and expands on the information in the book.
1. The only authoritative source of information on these matters, as you no doubt know, is the Spanish DGT (Trafico web site) or the Spanish consulate in the country you are leaving to move to Spain.
2. There is not such thing in the UK as a "baja de residencia", so the British Consulates do not issue them. This concept is related to Spanish citizens returning to Spain after living abroad. Spanish citizens have the legal obligation, unlike British citizens, to register their details in the nearest Spanish consulate, so they are considered as living legally abroad. When they return to Spain they need to show evidence that they have notified the consulate of their departure, hence the "baja de residencia". The concept is therefore meaningless to British citizens.
However, some Spanish authorities insist on demanding this requirement, so in order to avoid the conflict we offer the possibility of issuing an official certificate based on the customer's sworn declaration on when they left the UK. It is important to note that we do not certify the details on the declaration, but only that the customer has declared the details to be true. Also, not all the authorities request the document, so the customer must check beforehand with the appropriate authority.
This is the situation within our consular district. Other consulates may have different arrangements with the local authorities.
Customers requesting the certificate from us will be asked to provide their passports and a consular fee of (currently) €134.00. We will also request evidence that the customer has complied with the UK regulations on exporting vehicles, i.e. a Certificate of Permanent Export (V561) issued by the DVLA. More details in my book and at www.dvla.gov.uk.
The cost of the official certificate is now very prohibitive at €134 as it is merely a notarised, or sworn statement letter which can be obtained at a lawyer's office or the local town hall in the UK or in Spain, which is better as it will be in Spanish as well, all for considerably less. Trafico would accept this with the other relevant documents supplied with the application.
Updated 7 June 2007.