I just been over to Germany for a long weekend and I did not do anything to the lights.
Was told by the dealer as LED did not have to do anything.
Could not find anything in the manual about LED lights, only mentions for the halogen lights that need stickers.
BUT in the new 2018 Manual found this
Driving abroad
To drive abroad, the following must be taken
into consideration:
● For vehicles fitted with a catalytic converter
ensure that unleaded petrol is available for
the journey. See chapter ››› page 306, Fuel.
Automobile organisations will have information
about service station networks selling unleaded
fuel.
● In some countries, it is possible that your
car model is not sold, and therefore some
spare parts are not available or the technical
services may only be able to carry out limited
repairs.
SEAT importers and distributors will gladly
provide information about the technical preparation
that your vehicle requires and also
about necessary maintenance and repair
possibilities.
Adhesive strips for headlights
In countries where vehicles drive on the other
side of the road to your home country, the
asymmetric dipped beam may dazzle drivers
of oncoming vehicles.
To prevent dazzling, you must apply stickers
to certain parts of the headlight lenses. Further
information is available at any Technical
Service
So now even more confused wether we need stickers on the headlamps or not.