I had this too, took mine in for a software update and complained about the creaking, he told me it was the back of the seatbelt holder rubbing on the leather, he told me they will put a piece of felt on it to stop it, I expected some bodge job but got a very nicely cut and professionally done job that even had a cut out to read all the nonsense **** on the belt, and I haven't heard it since - but I have heard the passenger one do it, so when I go back i'll get them to do it on that one too (not sure why they didn't anyway)
The only thing that annoys me is the actual belt in the holder clicks around, especially when turning a corner or if I re adjust myself it clicks, I complained to them about this but apparently it's normal.. even though i argued the passenger one doesn't only if you really try to get it to click, which he tried himself (and did try) and still said it was normal! Oh and the belt tensioner/retractor - drivers side also - makes a clunking noise, so again if I move around it clunks right in your ear, and doesn't the otherside - he again tried to replicate it on the passenger side (and tried it so hard it did it) and said it was normal... I just shrugged it off as it doesn't bother me that much. Probably more hassle than what it's worth.
Not sure if you guys was meaning any of the above, but take it in and ask for the felt.
Can you take a picture of the fix? My local dealership needs pointing in the right direction to get the right fix at times so this one would be useful to know to save repeated trips back
I thought these seats already had the felt pad on the seat to belt clip contact area? I'll look tomorrow..