My A3 2017 2.0 TDI had a major service at the local Audi dealers last week. Today whilst topping up the screen wash I noticed that the underbody tray, visible from the engine bay, still had a lot of dust, small stones etc on it. I would expect anyone removing the tray would have dusted it off. Since access to the oil filter requires the tray to be removed I now gave some doubts if the dealer actually bothered to replace the filter during the service. The screws holding the tray also look as if they have not been touched. Am I correct that on the oil filter can only be reached by removing the under body tray?