I also tried to order the "semi electric" towbar when ordering via our preffered broker, and they stated it wasnt on their options screen - even though it was clearly listed on the Polestar website ordering site.
They did some digging and came back saying they were not installed at build due to the diff. countries laws/ requirements, and that he has placed a note on the file of my car for it to be installed when it arrives in the UK.
Not sure where that would be, ie portside or "dealer" (Volvo?), but he intimated adding to my order may delay the delivery.
I would have thought that all vehicles will be pre-wired for the Tow bar, esp as its not really electric, just a button that releases it from its hidden locked location and you manualy lock it into place.
Of course I could be totally wrong here...!