Hi. I have just purchased a 2018 Q5 S line with a factory fitted tow bar. I connect my caravan to the car just to make sure it all works & it did.
When I ordered my Q3 way back I had a big discussion over the electrics & the outcome was. As it was a UK spec car the towing electrics should meet UK requirements. If not the dealer should fit the missing cables free of charge beofre delivery.