If any of you are like me and have had to take the extruder apart a number of times and are terrified of losing the smaller pieces here’s something that might get you out of pinch till you can find or get a new part. It’s the lower filament guid in the extruder. I lost one a few months back but fortunately had a spare extruder that I could rob.
It’s the smallest thing I have tried to design print accurately I used PETG but something more temperature resistant might be appropriate. As usual if you print a spare before you lose yours you will never need the spare. 
More comments under each photo.
OpenSCAD model, can supply OpenSCAD and STL files if anyone is interested.
in situ
Underside exit point - printed at 1.95mm but had to ream it out with a 1.8mm drill bit
6mm high. I flared the entrance hole which is a bit rough because I printed without supports but, hey it works!
its 3.1mm wide and 7 mm long - could be a mm longer.
