To the best of my knowledge, yes.
I left the car with the auto electricians all week and they were unable to replicate the fault following the initial reoccurence with them described in my initial post. All the did was unplug various electrical connectors, clean up contacts if there was any hint of moisture/dirt, and reconnect.
Car has ran perfectly ever since with no reoccurence and still no fault codes.
It's gone - no longer an e90 330i owner