Well, that would do the scheme a lot of good press, Motability giving a 77 year old a car with excessive horsepower and dodgy eyesight and reactions.
Am sure that would float well with the Daily Mail.
We all had brilliant and exotic cars when we were younger, they were death traps, but at that age you were oblivious to the dangers.
Its getting to the stage now, where over 70’s will practically have to resit a driving test every 3 years.
As for your perceived treatment, that is from your perspective, if you let them do that to you.
If you are not happy with their service, ask to see the manager.