This afternoon I returned to the project, but without Jameson. Without him hanging about & me worrying about his safety, I planned to reconnect the starter cable & attempt to turn the engine over to cycle the oil through the system. With the bottom spark plugs removed & if all goes as planned, I should note a few pounds of oil pressure on the gauge rather quickly.
UPDATE: Well good news - bad news. The key switch that energizes the start circuit works unfortunately, when I press the start button the start C/B pops. Time to trace the wiring. My gut feeling is that the diode at the starter solenoid is on the wrong terminal or reversed. More fun tomorrow..!