Hi Richard, mine was worn exactly the same after 9K miles on our Roadster.. I pulled the pedal box assy when looking for a brake pedal issue and corrected the wear in the clutch arm/clevis pin at the same time by making a new pin. I re assembled with hi pressure grease, but due to the small bearing area between the arm/pin I suspect it will wear again. I believe some of the one sided pin wear is due to the angle your leg/foot pushes the clutch pedal together with inbuilt loose tolerance between pin and clutch pedal arm. Also as per your car, the flat washer was missing between the clevis and split pin and I agree having a washer fitted will help reduce the side twist on the pin.. When I stripped the pedal box I noted that the clevis pin dia used on the brake is larger than the clutch pin dia.. The larger dia pin gives a greater surface area to transmit the force and should reduce wear due to this.
In the future if the pedal arm pin hole wears oval it should be relatively straight forward to bore it larger and tig weld in a top hat type insert to bring it back to spec, or alternatively fill the area with tig weld and rebore.
I agree with all your thoughts and findings Dave and will keep fingers crossed regarding future wear. One hope is that stainless will wear slower.
I did look at a suitable rose joint solution but couldn't find anything that transmitted the force to master cylinder square on.
