All dealerships in my city are extremely overpriced and refuse to provide part numbers to customers. It's pretty disappointing.

I use a dealership thousands of miles away to get fair prices (shipping included) and have discussions on the proper part number if they aren't called out in diagrams.

The wheel well liner bolt part numbers aren't called out anywhere that they (or I) can find.

 

This might be it?
I went to Jaguar factory parts and typed in 2012 XKR. Next I typed in wheel well liner.
I got this list of parts and fasteners. They indicate the "Wheel House Liner Rivet". Part #C2S9354020. Note this web site does have diagrams to help and don't forget a quick E-mail to the dealer is often advised to make sure of the correct part.

Jaguar Parts Search

Now this might be incorrect and note there are several other fasteners listed. I would run these numbers to see if you can find any pictures.
Here is an EBay search and this is a very common number and there are pictures. Be aware that there are very similar fasteners but with some different dimensions. So get you old one and take some measurements. But these are cheap so maybe just go for it and buy 10 as they are under $10!

EBay part number search
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the one's that show up on that ebay search are similar to the ww fasteners on my x100 xk8, not the ones on my xk150...but, it is ebay you know
wj

 

https://www.jaguarparts.com/oem-part...vet-c2s9354020

there are two numbers - 5 and 6 in the illustration - on mine there are two types - threaded and more of a self tapper.

 

I just looked at mine...it appears that others have used what ever they had on hand when working on this car! I have the original one shown and the second one shown and two different types of push pin ones. So my reference is fubared. Sorry
wj

 

Yes, there are a couple of push pins too.