Yes, thanks to both Rhizome and Stinky Beat.
The manual is certainly less than clear on this.

Suffice to say the Project level Program change option can be left to ‘off’ and the Track specific program changes still work with external devices.

Similarly having the project level program change option ticked, and set to auto (and auto set to the correct channel for an external synth) also works, as long as you set the Project wide trig channels to ‘off’.

Topic closed !!