Hi,
i agree totally with you, I have no faith whatsoever in main dealers. Last summer I had an issue with an engine sensor which indicated that it may cause brake servo issues. So I asked the main dealer for some advice, which was "we will need to carry out a computer download to confirm the fault which is £140 before any work is done and cannot do anything for 4weeks it's summer holidays" . I then asked whether the car could be driven and his response was "I cannot possibly tell you that"
So I looked on Utube, the fault seemed fairly common and fairly simple to fix, however I erred on the side of caution and found a local mechanic who had recently retired who came to my house replaced the sensor in 10 minutes, provided me with an invoice from the part supplier and all for £120. Problem fixed.
That is why I have no intention of using the main dealer ever again particularly since I now found the guys who repaired the fuel flap actuator.