CAA examiners go to Jerez for one reason one because the FTO is appruve by the CAA ( I dont know if they are DGAC appruve but I know that they dont run the courses with the DGAC).
In Spain most of FTOs have their own examiners, I mean that the work for the FTO as instrucctor and as examiner ( If you fly with him underinstrucction you are not allowed to take the exam with him)