Picasso help regarding roof rail fixings

I’ve managed to acquire some official C3 Picasso roof rails. They fit fine but on installation I noticed one of the mounting bolts is damaged. It fits into the roof/body fine but the bolt the bolt won’t tighten. The thread seems damaged. Maybe when taken off the original car.
My question is does anyone know where I can get a replacement. Original or third party.
I’ve googled and ebay’d for a long time but get lost in loops. I’ve even tried the part number to no results.
Any help, pointers or links would be amazing.
Photo included

Try searches without the "dot" E.G. 8301EG.

I doubt very much that you will find them on Ebay, nuts'n'bolts stores or whatever, it's a fairly specialized part. You would have be lucky to jag one for sale by a private seller.
The price of parts is fixed (through dealers) all over the U.K. so it doesn't matter which dealer you go to the price will be the same.
There are a number of parts resellers who deal with the public like:

https://peugeotcitroendsparts.com/peuge ... ng-8301eg/

https://www.desiragroup.com/contact-us/

Or just go to Citroen?

Thank you for your reply and going to Citreon was my next step but wanted to check I wasn’t over looking anything.
Will check the links you provided