Brian, I'd be amazed if you found one on here, since they are 'special order' in the first place.
In my opinion, it is the way to go when running 17" wheels on an early Zed.
Best thing to do is go straight to Talon. Tell them you want a 5/8" offset, the same as they do for Debben..... That way there should be no confusion, & believe me, I have a mega offset sprocket to prove that things get confused, even with the clearest instructions.

Talon did remake it FOC though.
Cost will be around £60, but will get a little cheaper, the more you order.