A6 Woes And Dealer Incompetence

Hey Guys
Need some help regarding my sisters car. She's being given the run around by the local stealer, and it still ain't fixed.
Audi A6 2.0 Avant (1995 'N' reg).
The original problem was the rev counter would fluctuate and then drop to 0 (engine still running and driving car), followed by a bleep and the oil light illuminating.
Two reputable independent auto electricians looked at the fault, and advised that the dash insert (clocks) be replaced (circuit board in this unit was the identified source of the fault). These have to be sourced from Audi, and are reconditioned units supplied on condition of p/x for your old ones. They must be reprogrammed for the mileage and keys, and ONLY Audi can do this.
The first replacement dash insert was faulty, and not installed. Another was sourced, and Audi replaced the dash insert, but the original problem still occured along with some extra ones. The fan wasn't working, indicators and window wipers would not operate simultaneously.
Car was returned to Audi. Allegedly the fuse box was replaced this time, due to water ingress (of which there was no evidence).
Most of these faults are intermittent, but appear to be becoming more frequent.
Hazard warning light button constantly illuminated When fan is left switched on, the fan can switch itself on and drain the battery (car not running and locked at this point) Window wipers come on intermittently even though the switch is off. When key is removed from the ignition, there is a buzzing noise, which can be stopped by turning on the fan switch (the hazard warning light button fades, but does not go off).
Vehicle was returned again, and despite the above, Audi claim that there is in fact, nothing wrong with the vehicle. They are unable to locate a fault, even though (for example) the hazard warning light button is constantly illuminated.
If anyone has experienced similar issues, or has any idea what it might be please enlighten us! Failing that, I would love to find the customer services address of Audi UK, as this stealer seems unfit to be displaying the four rings (unless of course, they're all like that).
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.