I have a 2007 mdl 2.0 TDI DSG built Nov 2006. I also found that it was missing when I checked the oil, also could not understand why so much engine noise inside car in traffic. Seat UK + dealers confirmed that cover deleted from factory for 2007 mdl year. I argued that no-one had informed me when car ordered beginning of Nov 2006. Seat and supplying dealer split cost. It does not make a big difference, but it was the principle.
Just like deleting xenons on Cupra but forgetting to tell the customer! If you don`t ask you don`t get. Not as though car is cheap and a diesel needs more insulation and it looks unfinished without cover. same with service package, only found out on this site just after 1st service! Would have saved me money