I'll look into this mate as it might need some advanced comfort settings turned on in the cluster, but my 1st position on the wiper stalk turns my auto wipers actually on mate so if I kept on bottom they wouldnt work at all even if it rained.
The sensor is on the glass & its based on vibration of the rain on the glass so no that wont help fella, but if it really annoys you then you can remove the mirror & disconnect the sensor, but might get a DIS warning about this but it will definitely turn of the auto wipers, I'll see if there's anything on this that isnt a vagcom job so you can do yourself.
My wipers when on auto respond to the frequency of droplets on the sensor so more rain more wiper movement, isnt down to the delay set on the stalk, as yours should do mate, given ite new just pop into audi for now as they will do for free, blag it saying the auto wipers wernt turned of as I requested when I picked up the car, lol.
Unless you buy vagcom mate, hint hint, compliment your new car nicely.