Well at least you have the right to complain to the dealer and you can sue them and BMW uk with them if they do not put the car back to initial condition.
Did you complain to your insurance to let them put the pressure on the dealer?
In my case my wife wanted to spare some water (too costy obviously) when she helped me to wash the car.
Now I have scratches on the clear coat on the full car, and on black it is really obvious.
Few cents of water saving for few hundred euros of paint repair... I can not sue her or even complain too much
Going to try some polishing by myself when the good weather is back... If it does not work then I will go to a professional.