OK
With the screwdriver (in the ignition) to engage the starter - nothing
With the seat sensor bridged - nothing
With the ignition off and the seat sensor still bridged AND the two large terminals on the solenoid bridged ... she starts right up !! and the transmission was in reverse (more or less) !!
And she continues to run even after I remove the seat sensor bridge and I disconnect the battery negative !
More work, more testing ..