The original metal one didn't last long. I hope this one holds better. The design is based on other plastic mudguard holders.

You can easily adapt the part to your mudguard: Open the FCStd file with FreeCAD and change the parameters in the dimensions sheet.
mudguard_width How wide must the holder be inside?
mudgaurd_hight How high must the holder be inside?
mudgaurd_thickness Thickness of the mudguard material