Question I was looking for an answer on how the Utility : Program Bank : External can be used Can I toggle between factory and user programs using either CC's or program changes

Yes, the External option allows the M-One / M-One XL to switch between the factory and user banks, when recieving a MIDI bank select message (MIDI CC 0 & 32). If Prg Bank is set to either User or Factory, bank select messages will be ignored.