Sorry, not much help, hopefully @Glos Guy can assist!
Not an area that I can help I’m afraid. Is this the new Motability insurance company? Reason I ask is that I have had Enterprise hire cars a number of times over the years (provided by Motability) and never had to do this. In these cases it was when the courtesy car that was going to be provided whilst the car was in for repair was unsuitable (too small). I haven’t had a situation where there’s been a 3rd party at fault, but given how challenging the financial situation of many Motability customers, and the number with anxiety and other mental health issues, it seems unacceptable to me that an organisation sitting on as much cash as Motability expects customers to have this worry, especially when it’s not their fault. It’s meant to be ‘worry free motoring’ after all. I’d be taking Motability to task over this.