I feel your pain. I went through this some years ago when someone claimed my wife’s 3 month old Micra had managed to write off their Honda Accord in a car park, despite there not being a scratch on her car.
How a plastic bumpered purple Micra could write off an Accord by hitting its chrome steel bumpers and not leave a scratch is quite something. The damage to the other car was a completely destroyed wing, headlamp etc and bent chassis member, hardly superficial.
We fought with our insurers, Direct Line, for several weeks, all to no avail, they paid the claim & billed us for the excess. We think it was settled that way as the other driver was also with Direct Line.
In life, it's not who you know that's important, it's how your wife found out.