I’m so sorry to hear your issues with your new car. Dealers need to allow motability customers to test drive a car identical to the car that we would potentially be getting. When I test drove an X1 I had it for 24hrs and couldn’t wait to hand it back, that came at a £250 refundable deposit for the 24hrs though. But was well worth it.
I hope you get things sorted, sorry I have no useful advice as I’ve never had a motability car waiting for my first.