I dont know how to reply seperately so here goes a joint response.
Firstly, thanks for advise about Reeves, i have used them for steamy bits but didnt think of them for this.
Yes, i too sent C and H suppies an email which was ignored, same with several other US suppliers. I did get my sprag clutch from them but i used the services of a friend in Texas so they are still in stock at 15$ each. Try phoning him rememberings he is only open on Friday and Saturday.
If you cant get one from C and H then you could easily desing and build your own using the one way roller bearing and a seperate sprocket- this was my Plan B if C and H didnt come good.
Regards
Trevor