I am struggling to see what you would base your claim on, what losses you could claim compensation for.
Did you pay more for leasing your car because you believed it was more environmentally friendly? Was the petrol version cheaper?
You didn't lose out financially when you changed your car, as owners did if the scandal caused the value to drop.
I have owned my 13 year old diesel from new but can't claim because I didn't base my decision to buy on the emissions claim, I took no notice of that data. I haven't suffered any loss because I don't intend to sell it