Yeah that’s why I said hopefully they’d get a car that would suit everybody…. another option would be to let them use your motability car. That way they’d save money on running their own car but be driving a vehicle suitable for you?
There’s no easy straightforward solution as the one who has “your” car may not be available when needed.
You could investigate and make a list of suitable taxis nearby but sounds like the best solution would be to keep the Tiguan for a while longer while you consider what’s best for the long term.
If you haven’t already then I’d change all the named drivers for the Tiguan so it can be used ?