- Hold down set for a couple of seconds
- Hold down 1/2/3 for a couple of seconds and you'll get a "bong" to indicate that the seat/mirror positions have been saved
The fix was to move the seat to every extreme - all the way forward, all the way up, all the way down, flatten the back, make it upright, lumbar position, etc. After doing this the car gave no feedback, but when I tried the buttons they had come back to life.
I thought I'd share this in case somebody else is searching for the same thing on their Enyaq!