Hi Shaun
Welcome to the Forum
I have read several times about this problem though not seen/suffered one myself
From what I read the only solution is change the unit two choices, first BMW I have read £1k+ quotes and long wait times for parts. Second choice a used replacement first use www.realoem.com put the last 7 digits of your Vin into the search box it will call up your model get the Part Number for your car, double click the part number and it should show a list of any alternatives if they are available. Then Google to find the part and check prices Apparently it isn't a major issue to swap a DIY job then get your Mech friend to clear and reset codes
Good luck
Dave