Replacement Extruder Arm

[Rumples]

I'm getting a lot of extrusion problems due to a clicking head. No matter what I try to change the tension in the extruder, the motor can't get a good grip on the filament. I think i need to replace my extruder arm with a metal one, but I'm struggling to find the part.

Anyone know where to get custom parts for the Pro W that ship to the UK? Or if the parts from any other types of printers would fit?