Insurers are very unlikely to pay for oem. I work for a BMW dealership and we get lots of people asking to have their screen done in our workshop. We advise them to speak with their insurer and that is usually the last we hear of them. The most an insurer has ever offered to pay for complete job including vat is £200. A 1 series screen costs between £600 & £700, the bigger models go up from there.
We had an old fella come in with a very high spec 530GT a few months ago, he had cracked his screen and wanted only an oem repalcement because of all the sensors his screen had in it. We advised him to speak with his insurers, he did this and then came back to us to book in explaining they had authorised all the work. We fitted his new screen at a retail rate of £1350 inc vat, he came to pick up and expected just to pay an £85 excess. We contacted his insurers and they agreed to only pay £200 towards his invoice! We informed him of this and as you would imagine he kicked off just a bit. He paid for the screen on the day but was blaming us for having to pay £1150 for a new screen??