hard to find (single use) fasteners

[ouch]

Any suggestions as to where I can find a supplier (preferably) for some of the more exotic fasteners Audi have chosen to use on my car? I'm finding a lot of fasteners are now out of stock with the dealers, and Audi-tradition don't list this particular one I'm looking for either.

I'm looking for some M10 - 12-point drive flanged bolts with captive serrated washer. I've tried regular capscrews but a creak from that area suggests things aren't being held properly.

Are there any places out there that specialize in small batch exotic fasteners such as what I'm looking for?

[paintman]

https://www.bresco.com/index.html
Worth a look.

[GreenV8S]

Maybe use Nordloc as a substitute for the captive washer?