Gear change shaft splines....GRRR!

[Barney Rubble]

Hello from South Cheshire!

For my 1971 Starfire 250.

I am looking at a worn spline on said shaft. I see Draganfly do a repair service, but wondering if anyone knows where I can get one off the shelf ready to fit?

I also wouldn't mind getting one on an exchange basis like you can do with car parts, where the old one can be returned after fitting the new one, whereupon you get your core surcharge back.

This is to save leaving the engine cases open waiting for repaired unit to be turned around; i.e. get a replacement and do the job in one hit, then send old one in at leisure. Any ideas? Or complete shaft assemblies available anywhere?
Have we anyone in the ranks who can fix these?
Thanx folks!