I had this problem and solved it myself.
Te problem most likely is that the plastic pieces connecting the motor to the flaps. Cheap item hard to replace.
Bad news: it's about half as bad as replacing a clutch ..only less room.
It might be easier for you as the motors you are after are on the passenger side for the right hand drive models.
To do it the normal way you need to take out the doors, the seats, the steering column, the head unit, the dash display, the arm rest, the center console, the dash, then a metal brace along with the ac unit( the big thing that has the evaporator and the heater and the flaps..etc). The elearn manual says to remove the coolant and the freon as well.
When you get to this point you actually have access to the flap motors.
What i did ( for a left hand drive car):
I took out the steering wheel column and the plastic covers ( you might have to remove the glove box..and other panels in theway) in order to get to the metal strut piece it's made out of aluminum; then i drilled a hole in it in order to get some access to the screws thats ecure the motors to the unit there are 3 screws for each motor.
Then I spent 6 hours on my back under the dash trying to get the screws out, used 1/4 sokets with flexible extensions and u joints and extensions...etc