Oh well, If you ever fancy a bit of a long day trip give me a shout and I will put the kettle on!!!! lol
The modification viewpoint is prob one that has the possibility to start a long running debate, my view is that this not really a mod. The control module already has the feature available (yet to be seen on your 2017 model) and all that is being done is that this is being switched on.
What I can tell you is that with the feature working you would have to know that the mirrors do not fold immediately. When you lock the car you have to hold the lock button for around 2 seconds and the mirrors will then fold in (not something most people would normally do.
If you can find someone with the correct lead and software (who knows what they are doing) near to you then they would also be able to put the car back to standard when you were to return it that the end of the lease. As no physical mods have been done, you just un-tick a box in the module software and hey presto, factory standard settings return.
It is one of the many baffling things I find in the VW Group setup. That it was never even offered as an option is weird. My MY13 SE Lux (top of the range at the time) also didn't have auto fold, but it isn't just a Seat thing as some Skoda's are the same and my wife's last car (2011 Passat) had factory folding mirrors but there is no way to get them to fold off the key at all.......
Not the weirdest thing though. That is the fact of why would anyone buy a VW Sharan, when you can buy the same car (the Alhambra) with load more standard Kit, built in the same factory by the same people, but pay loads more for it. I am waffling now aren't I...............
Anyway, good luck trying to get it sorted....