Engine code on boot sticker and cam belt cover BYD
Stitched steering wheel with flat bottom
Stitched gear lever gaiter
K04 turbo with DV relocation ( the DV is under the bonnet between engine and battery, rather than hidden on the turbo )
Might have a plaque on end of dash but not all were fitted
Colour coded bottom section of bumpers and sideskirts with extended front lip on front bumper
One thing hard to fake it will say 169kw on the V5 log book for engine data
I'm sure there's other bits.
Mine came with a letter from VW with all the options printed out including the option of Edition 30. I'm sure your local dealer would check on their system for you to see if its a genuine Ed30 from the vin.