Does a main dealer really spend £500 doing up a car that they are going to sell for £3500 max. Maybe a hoover and a wash would be sensible, even an MOT, but dent removal, a full service...? That's mad!
Do main dealers even usually sell £3500 10 year old 70k mile cars that they've taken in P/ex for a grand?
Never seen round here. I think they just stick them in an auction for 'dishonest' John to buy and stick at the side of the road with a price in the window

I assume main dealers make their profits on newer cars from fleets, PCP, motability or whatever plus all the extras they add on