I finally pulled it all apart today - Was worried I was going to cost myself more by stuffing it and needing a new motor but I forged ahead and I'm glad I did.

The sensors were just clogged up with grease from the gears. A simple clean with degreaser and the mirror works as new.

Tools Needed
1. Medium Phillips Head Screwdriver
2. 10mm Star Driver
3. Two flathead screwdrivers (for levering the mirror off and the bracket off the motor)
4. Degreaser
5. An old toothbrush



NOTE: My left mirror is the passenger side

Pull the mirror and electrical connections off and remove the mirror motor from the body by removing the 4 phillips head screws



This is the tricky bit, you have to pry the mirror bracket off the motor so first pop it off the centre ball and socket joint (by putting your two screwdrivers in and levering away from the motor)



Then (careful not to snap anything) pry each of the 4 arms out of their retaining clip.



Remove the rubber seal completely and remove all 6 star screws.





The two sensors just slide out so if you can't get them out with your hands you may need some small pliers. Clean them off with some degreaser (On a cloth or a paper towel)



Then remove both arms from the housing and clean off the small metal connectors with some degreaser and a toothbrush. Once clean make sure to bend them slightly away (without breaking them) from the arm so that a good connection is made with the sensor when reinstalled.



Put it all back together by doing that in reverse and you're done.