You would use a lawyer in your home country when buying property and there is no reason why you should deviate from such common sense when buying property in Spain.

Many Spanish lawyers speak excellent English, among other languages, and are accustomed to dealing with foreign purchasers and advising on their property transactions. The best way to locate one is to ask around for personal recommendations and experiences.

Alternatively, the British Consulate maintains a list of lawyers who speak English.

The lawyer will charge you around 1% of the value of the transaction, unless there are some unusual complications.