Here's a follow up. This book covers the orginal Palantype keyboard layout and method. When Possum Controls Ltd introduced a newer version, in the 90s, they changed the layout slightly and also provided a new manual.
There is a version of that manual called:
Possum Palantype C.A.T. System
Operator Training Course
Copyright Possum Controls Limited, 1997
There may well be other manuals available too. I am hoping that at least one current Palantypist will show, lend or sell me one. But I am not willling to pay the hundreds, or thousands, of pounds that they orginally cost.
The British Library has no copies of later training manuals. At least none that I have found yet.