As someone who works in the motor trade, working with a lot of motor factors (selling my product into them), welcome to the misogynistic, antiquated industry that is the motor trade.
I've seen this a lot, super star sales people who are women but never end up making it into higher positions because it's a boys club. Not right but it's just the way it is and will probably be a generation or two before it's really any better, hopefully.
My advice would to be get out of the motor trade, it's full of absolute lemons who think they're **** of the walk and the best thing since sliced bread.
The skills she's developed sounds like she could work in any company in a customer facing sales role, maybe something that she's passionate about if it isn't cars!
If she wants to stay in the motor trade, then if she's currently in a big national motor factor, then start getting in contact with the smaller independents. They usually care a
bit more about their staff, although this does come with a smaller company mentality = more responsibilities, but it sounds like she's not shy of putting in the effort to get the results!
That and they'll have cleaner toilets than the motor trade, ask her about the worst toilets she's been to in a garage/bodyshop and i'm sure she'll have some horror stories