DeeBee, just a thought but have you tried giving Motability a call and seeing if they have any record of the car / its history?
Looking at it from a slightly different angle if it had been accident damaged during the lease I’d imagine the repairs would have done at a main dealers or similar approved workshops, admittedly it doesn’t guarantee a 100% quality repair but at the same time it wont have been bodged by some cowboy working from his driveway either.
There are also a couple of minor things to look out for that can sometimes give an indication of a car being ex Motability, for example Vauxhalls and possibly Fords of that age came with parking sensors even if they weren’t standard on that trim – going on that a base spec car with no extras apart from parking sensors has a decent chance of being ex Motability. The MOT history can also be a clue as Motability do it around a month before its actually due, the online check for your reg numbers shows the first MOT being pretty much exactly 2 years and 11 months from the date of registration.
**EDIT**
Ok, so none of the above is much good in proving when any damaged occurred but may help confirm if it really was a Motability car.