I serviced my own a4 avant last week, it has full service history but i'm not getting stitched up by the stealers, oil change was easy cost me £25 for the oil and new filter, drained off my fuel filter.. again easy,checked gearbox oil level and greased up all the hinges which is basically what they do anyway on a service.
Only thing that needs doing is the cambelt which i will pay out to get done.