the reality is all of these online company's like DA are valued on the basis of number of e-clicks / users, its likely DA will be hoping at some point to cash out the same as autotrade-mail did with selling to autotrader, DA will have zero appetite for getting rid of dishonest sellers as it affects the numbers, regulating it so the seller has more credibility only earns that seller more money, it would not earn DA any extra money, like all online based company's the value is in the amount of users - not the quality of the users, hence its unlikely things will change.
if they start telling the vendors how they "must" use the system - the dishonest ones leave and the honest ones take offence because in their eyes they were doing things right anyway, the result is the platform becomes worth less money, instead its easy for DA to quote "guidelines" for sellers which we know is not worth toffee.
i only ever used the site once the result being an arrogant sales manager thinking i was mug of the week ,so i decided to police the situation myself - bought an a4 avant from an audi franchise, phone call later all good and we will see you tomorrow for collection, i drive 130 miles with my trailer, car looked great, i say is it ok too run it up the road, yes fine they say see you in a while, result is the gearbox is winding-badly, i return the car and leave, could not at this point even be bothered to speak to them, i set off for home and ring them, the cocky manager says its a trade car and the local trade buyers would have take the problem on the chin, i say they havn't though have they hence youv'e dragged me 130 miles to try and took me up on DA, i tell him iv'e left the keys on reception and hang up, half hour later he rings me saying cant find the keys, i tell him again left on reception and hang up, over the next few hours they keep ringing and i just ignored them, they never did find the keys because they came home with me...not a nice thing to do but f**k them they deserved it.