Thats not the outcome we was all hoping for.
Sadly i had the same thing with my problem where they footed most of the bill not all of it. Mine was not as expensive as yours so i didn't involve a solicitor etc and settled. I did chase them further but all communication i got at that point was that that once the decision is made it was final on their part. Be intersting to hear how you get on from here. I wish you the best luck.
Did you get a courtesy car? If you have a dealer asset they may help you chase to get it reaolved asap.