Vortex implemented their own version of CP/M for the CPC, this page describes that. They didn't use Amstrad's version.
Vortex's implementation of CP/M on Floppy
To boot C/PM you need:
- a CPC464
- VDOS 1.0 on ROM and a Vortex disc interface.
- a 80 track double sided drive A.
- a Vortex 512KB RAM Expansion.