It's just the diaphragm type spring washer used to hold the heat shield on. Provided you are careful about taking it off, and then flatten it, you should be able to re-use it.
Hi Mike, I recently bought a bag - minimum 20 I think, only a few quid. Don't know the part number but it will be on the bag. As Richard says, you can re-use them if they come off cleanly or not too bent up.
Sorry to be so slow, I just managed to retrieve them from the Xantia and yes, you've got the right part number. I can spare a set if you want them, just need to keep a set or two as I'm sure I'll be having to pull them off again sometime. PM me your address and I'll get them off to you on Monday.
