I changed the rad in my Q4 which has got aircon, also alot less space behind the fan because of a dirty great turbo.
From memory the rad needs to come out ouf the top of the car, and to make things easyier you need to get the front slam panel, with the lights out, the bumper too, you should then be able to undo the bolts holding the aircon rad, and also the fan, basically undo all of the piping for the cooling rad and drag it carefully up. From what I remember the rad is bolted at the top but has a couple of 'pins' that push down into rubber gromits at the bottom.
Will probably take the best part of a day to do, but it is fairly straight forward. If you need any more help just ask.