I'm not much of a techie, so apologies if this is a silly question! The air con has stopped working, it's not the fuse, so is there anything else I can do / check out before I admit defeat and call in the professionals? Any ideas / help much appreciated!

did you check the wire at the ac compressor to see if it is connected and check your ac switch in the car to see if it has corrosion but if you are not much of a mechanic i would recomend you bring it to the nissan dealer cause you can actually make it worse, no offense.