Anthony, if you look at this thread by KeyboardByBiggs at PSR Tutorial forum, there may be some thing of interest regarding add leslie effect at Genos.

Thanks Gunnar,
They look very interesting and sound like a Leslie sim should.
Will look further into this.
Glad that others agree that Yamaha should have done the job properly on it's flagship keyboard.
Would still like to know how Chromatic Paul achieves his sound though. The guy's a real class act.
Tony