Checking for options - some of them are of course obvious - othes I guess you would need the build codes and be checking in the boot for the data sticker. I will get the ball rolling...
Heated seats - buttons on the centre console
Heated washer jets - build code???
Low washer fluid warning light (does this come on momntarily on start up?)
headlight washers - small doors below headlamps
Xenon lamps - different appearance from halogen (and no leveling dial next to light switch)
Park assist - button near gear stick and extra sensors on wheel arches
High beam assist - left stalk has two forward positions (auto and on)
Dynaudio - Dynaudio badged speakers throughout car
Nav Pro - larger (8") screen
Lane Assist -
?
DCC- extra button near gear stick?
ACC (Adaptive Cruise) - radar sensor on front grille (plus steering wheel buttons)
Rear camera - engage reverse and check media screen!
Performance Pack (GTI) - build code??
Sunroof - obvious!
Keyless - no ignition key receptacle...
Tyre pressure monitor (re-set button in glove box???)