2005 Seat Leon central locking

i used the non remote key to open and drive my car the other day when i opended it it maid a beep sound,drove with no problems.when i parked up then locked the car as i was walking away the alarm went off,opended car turnded ignition on and alarm stoppded.the following morning my wife tried to open the car with the remote control pressed once to open drivers side door but the door remainded locked pressed twice all other doors opened but drivers side door remained locked.had a look in the car booklet and have resycnced the key with the car,this works but after a few hours the same problem happens again,any ideas?please