Road tax is renewed by you. You will get your renewal notice and will be able to take that to a post office and it’ll be stamped off as a disability exempt car. I don’t know if it can be done online, I only have experience of my parents doing that. Breakdown, you get a number to call, they’ll have all your details from Motability, same with insurance. Your dealership will let you know when servicing is due and will book it in with you. They’ll also provide a courtesy car while they have yours.
That may be the case with your Id3 when you get it or any EV ?
Seriously Motability sort the VED from their end on any vehicle regardless what its powered by!