Alex, you should have let them clean the car after repairs, it's very hard for a repairer to do a good quality check when a car is covered in dirt and dust, bodyshops where ever you go has a dusty inviroment it's the nature of the business.
The bodyshop where i work we clean cars before they go in for repair so we don't miss any imperfections on the panel being repaired, they are then blown off frequently while in the workshop with air lines so cars stay clean through out repairs. Then when cars are completed they go off to be clean with a jet wash this cuts down the need to use sponges that could have grit in them. After washing the cars they are then polished and waxed on all new painted panels and adjacent panels, before going for final quality checks.
What i dont like hearing on these forums are people always slating repairers, because it gives us all a bad name. If bodyshops are all useless like some poeple seem to be saying, you dont have to use us, you can always keep the damage on your cars. Or as there seem to be so many "experts" out there you could all go to halfords get some filler and a couple of spray cans a do the work yourselves, i would love to see the outcome.
Neil.