agnese klavina , 30 , vanished from puerto banus resort on september 6 .
had been on night out at aqwa mist nightclub popular with rich and famous .
westley capper , 37 , has already admitted driving her away in a mercedes .
he declined to answer questions in appearance before spanish judge .
co-accused craig porter , 33 , was in the car and also said nothing in court .
capper 's dad john specialises in buying and selling luxury properties .