Graham Phantom 1 Owner's Manual

Have you looked over on vinylengine.com? You have to register to view library.

https://www.vinylengine.com/library/graham/1.5.shtml

Thanks for the link, looks like a great resource.  Sadly, no Phantom manuals.  The search continues.

This may seem an obvious question but have you tried Bob Graham himself? He is a busy man but will get back to you.
 Bob also has agents in the U.S. who are happy to handle the day to day business (upgrades etc) on his behalf).

Thanks much, that would be my next move.  For better or worse, I'm usually reticent to reach out directly to a builder or dealer for something like a manual when I've purchased the piece second-hand.