Had the same thing just before Christmas.

Screen was cracked on the M50. I contacted the insurer and they advised All Glass would be the company to replace. I had already checked the fine print on my insurance and saw that the screen can be replaced elsewhere with a max payout from insurance up to 400 euro.

I priced the screen in BMW and there was less that 100 quid difference but they guarantee the work and that the rain sensor will be fully functional.

Handed it to BMW to replace and then emailed a copy of the invoice to my insurer who actually paid me the full value of the screen replacement - which was above the 400 euro limit

Happy Days