There have been a few requests for suppliers of Citroen spares.
Quite a few have been offered, GSF being the prominent one.
Also a few breakers.
While looking for something completely different* I just stumbled across this one: Breakeryard.com
Looks nice, apart from that I knows nuuuuthin'.
*a history of Citroen innovation that had the hydraulic drivetrain in pre-production (on a Xantia, IIRC)